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A -
abdomen - the area between the diaphragm and the pelvis
abdominal cavity - superior portion of the abdominopelvic cavity
that contains the stomach, spleen, liver, gallbladder, pancreas, small
intestine, and most of the large intestine
abdominopelvic - inferior component of the ventral body cavity that
is subdivided into an upper abdominal cavity and a lower pelvic cavity
abduction - movement away from the axis or midline of the body or
one of its parts
abortion - premature loss (spontaneous) or removal (induced) of an
embryo or non-viable fetus; any failure in the normal process of
developing or maturing
abrasion - a portion of skin that has been scraped away
abscess - a localized collection of pus and liquefied tissue in a
cavity
absorption - the taking up of liquids by solids or of gases by
solids or liquids; intake of fluids or other substances by cells of the
skin or mucous membranes; the passage of digested foods from the
gastrointestinal tract into blood or lymph
accommodation - a change in the curvature of the eye lens to adjust
for vision at various distances; focusing
accretion - a mass of material that has accumulated in a space or
cavity; the adhesion of parts
acetabulum - the rounded cavity on the external surface of the
coxal (hip) bone that receives the head of the femur
acetylcholine - a neurotransmitter, liberated at synapses in the
central and peripheral nervous systems and at neuromuscular junctions to
stimulate muscle contraction
achlorhydria - absence of hydrochloric acid in the gastric juice
acidosis - a condition in which blood pH ranges from 7.35 to 6.80
or lower
acinar - flask like
acini - masses of cells in the pancreas that secrete digestive
enzymes
acoustic - pertaining to sound or the sense of hearing
acromegaly - condition caused by hyper-secretion of human growth
hormone (hGH) during adulthood; characterized by thickened bones &
enlargement of other tissues
acrosome - a dense granule in the head of the spermatozoon;
contains enzymes that facilitate the penetration of a spermatozoon into a
secondary oocyte
actin - the contractile protein that is located in the thin
myofilaments of a muscle fiber (cell)
acuity - clearness or sharpness, usually of vision
acupuncture - the insertion of a needle into a tissue for the
purpose of drawing fluid or relieving pain; also an ancient Chinese
practice employed to cure illnesses by inserting needles into specific
locations of the skin
adaptation - adjustment of the pupil of the eye to light
variations; the property by which a neuron relays a decreased frequency of
action potentials from a stimulus of constant size; decrease in perception
of sensation with continued stimulation
adduction - movement toward the axis or midline of the body or one
of its parts
adenohypophysis - the anterior portion of the pituitary gland
adenoids - the pharyngeal tonsils
adenosine triphosphate - universal energy-carrying molecule
manufactured in all living cells as a means of capturing and storing
energy; it consists of the purine base adenine, the sugar ribose & 3
linearly-arrayed phosphate groups
adenylate cyclase - the enzyme that converts ATP into cyclic AMP;
it is located in cell membranes and is activated when messenger molecules
(e.g., neurotransmitters or hormones) bind to specific molecular receptors
on the cell surface
adherence - firm contact between the plasma membrane of a phagocyte
and an antigen or other foreign substance
adhesion - abnormal joining of parts to each other
adipocyte - fat cell; derived from a fibroblast
adrenal cortex - the outer portion of an adrenal gland; divided
into three zones, each of which has a different cellular arrangement and
secretes different hormones
adrenal medulla - inner portion of an adrenal gland; consists of
cells that secrete epinephrine and norepinephrine in response to
stimulation of preganglionic sympathetic neurons
adrenergic fiber - a nerve fiber that when stimulated releases
norepinephrine (noradrenaline) at a synapse
adrenocorticotropic hormone - hormone produced by the
adenohypophysis (anterior lobe) of the pituitary gland; influences the
production & secretion of certain hormones of the adrenal cortex
adventitia - the outermost covering of a structure or organ
afferent arteriole - blood vessel of a kidney (nephron) that
subdivides into a capillary network called the glomerulus; there is one
afferent arteriole for each glomerulus
agglutination - clumping of microorganisms or blood corpuscles;
typically an antigen-antibody reaction
agglutinin - a specific principle or antibody in blood serum;
capable of causing the clumping of bacteria, blood corpuscles or
particles; also called an isoantibody
agglutinogen - a genetically-determined antigen located on the
surface of erythrocytes; basis for ABO grouping and Rh system of blood
classification; also called an isoantigen
agnosia - loss of the ability to recognize the meaning of stimuli
from the various senses (visual, auditory, tactile)
agraphia - an inability to write
airway disruption - Fractures or tears of the upper
airway may occur without causing overt obstruction. However, they may
impair ventilation and oxygenation. The diagnosis starts with an index of
suspicion based on the mechanisms of injury and presenting problems such
as stridor. A pneumothorax with subsequent large air leak following tube
thoracostomy or the presence of mediastinal air are additional clues.
Evaluation is usually carried out with the aid of flexible bronchoscopy.
Definitive treatment will depend on the location and severity of the
injury as well as the resources available. Temporizing measures include
selective intubation and ventilation beyond the area of injury.
airway obstruction - Airway patency and air
exchange can be assessed by examining for air movement and watching chest
excursion, listening for stridor, and looking for obvious lower neck or
upper chest injuries that may compromise the airway. If airway patency or
the patient’s ability to protect the airway are in question, a more secure
airway is needed. Endotracheal intubation is the first step, with care
taken to protect against cervical injury. If an airway injury is
suspected, rapid evaluation by means of flexible bronchoscopy may be
necessary to identify the injury. Furthermore, bronchoscopy may be an aid
in obtaining a patent airway, particularly in the patient who may have an
unknown cervical spine injury. Emergency airway maneuvers such as
cricothyroidotomy may also be necessary during this period.
albinism - abnormal, nonpathological, partial or total absence of
pigment in skin, hair and eyes
albumin - the most abundant (60%) & smallest plasma protein;
functions primarily to regulate osmotic pressure of plasma
albuminuria - presence of albumin in the urine
aldosterone - mineral corticoid produced by the adrenal cortex;
brings about sodium and water reabsorption and potassium secretion
alimentary - pertaining to nutrition
alkaline - containing more hydroxyl ions (OH-) than hydrogen ions
(H+) to produce a pH of more than 7
alkalosis - a condition in which blood pH ranges from 7.45 to 8.00
or higher
allantois - a small, vascularized membrane between the chorion and
amnion of the fetus; serves as an early site for blood formation
alleles - genes that control the same inherited trait (such as
height or eye color); they are located at the same position (locus) on
homologous chromosomes
allergen - an antigen that evokes a hypersensitivity reaction
allergic - pertaining to or sensitive to an allergen
alveolus - a small hollow or cavity; an air sac in the lungs;
milk-secreting portion of a mammary gland
Alzheimer's disease - disabling neurological disorder characterized
by dysfunction and death of specific cerebral neurons; this results in
widespread intellectual impairment, personality changes, and fluctuations
in alertness
ambulatory - capable of walking
amenorrhea - absence of menstruation
amnesia - a lack or loss of memory
amniocentesis - removal of amniotic fluid by inserting a needle
transabdominally into the amniotic cavity
amnion - innermost fetal membrane; a thin transparent sac that
holds the fetus suspended in amniotic fluid; also called the bag of waters
amniotic fluid - fluid in the amniotic cavity, the space between
the developing embryo (or fetus) and amnion; the fluid is produced
initially as a filtrate from maternal blood and later, from fetal urine
amorphous - without definite shape or structural differentiation;
pertains to solids without crystalline structure
amphiarthrosis - articulation in which the articulating bony
surfaces are separated by an elastic substance to which both are attached;
the mobility is slight, midway between a synarthrosis and a diarthrosis
ampulla - saclike dilation of a canal
amyotrophic - amyotrophic lateral sclerosis (ALS) - progressive
neuromuscular disease characterized by spinal cord motor neuron
degeneration that leads to muscular weakness; also called Lou Gehrig's
disease
anabolism - synthetic energy-requiring reactions whereby small
molecules are assembled into larger ones
anaerobic - not requiring molecular oxygen
analgesia - pain relief
anaphase - the third stage of mitosis in which the chromatids that
have separated at the centromeres move to opposite poles of the cell
anaphylaxis - against protection; a hypersensitivity (allergic)
reaction in which IgE antibodies attach to mast cells & basophils, causing
them to produce mediators (e.g., histamine) leading to greater capillary
permeability, smooth muscle contraction & mucus secretion
anastomosis - an end-to-end union or joining together of blood
vessels, lymphatics or nerves
anatomical position - a position of the body universally used in
anatomical descriptions in which the body is erect, facing the observer,
the upper extremities are at the sides, the palms of the hands are facing
forward, and the feet are on the floor
anatomy - the structure or study of structure of the body and the
relation of its parts to each other
androgen - substance producing or stimulating male sex
characteristics, e.g., the male hormone testosterone
anemia - condition of the blood in which the number of functional
red blood cells or their hemoglobin content is below normal
anesthesia - total or partial loss of feeling or sensation, usually
defined with respect to loss of pain sensation; may be general or local
aneuploid - a cell that has one or more chromosomes of a set added
or deleted
aneurysm - a saclike enlargement of a blood vessel caused by a
weakening of its wall
angina pectoris - pain in the chest related to reduced coronary
circulation; it may or may not involve heart or artery disease
angiography - X-ray examination of blood vessels after injection of
a radiopaque substance
angiotensin - either of two forms of a protein associated with
regulation of blood pressure; angiotensin I, produced by action of renin
on angiotensinogen, is converted by a plasma enzyme into angiotensin II
which releases aldosterone
anion - a negatively charged ion; e.g., the chloride ion (Cl-)
ankyloglossia - tongue-tied; restriction of tongue movements by a
short lingual frenulum
ankylosis - severe or complete loss of movement at a joint
anomaly - abnormality that may be a developmental (congenital)
defect; a variant from the usual standard
anopsia - a defect in vision
anorexia nervosa - a chronic disorder characterized by severe
self-induced weight loss, body-image and other perceptual disturbances, &
physiological changes resulting from nutritional depletion
anosmia - loss of the sense of smell
antagonist - a muscle that has an action opposite that of the prime
mover (agonist) and yields to the movement of the prime mover; a substance
which blocks a receptor site where a specific molecule (agonist) binds
antepartum - before delivery of the child; occurring (to the
mother) before childbirth
anterior - nearer to or at the front of the body; also called
ventral
anti-oncogene - a gene that can cause cancer when inactivated
inappropriately
antibiotic - literally, antilife; a chemical produced by a
microorganism that is able to inhibit the growth of or kill other
microorganisms
antibody - a protein produced by certain cells in the body in the
presence of a specific antigen; the antibody combines with that antigen to
neutralize, inhibit, or destroy it
anticoagulant - a substance that is able to delay, suppress, or
prevent the clotting of blood
antidiuretic - substance that inhibits urine formation
antigen - any substance that when introduced into the tissues or
blood induces the formation of antibodies and reacts only with its
specific antibodies
antrum - any nearly closed cavity or chamber, especially one within
a bone, such as a sinus
anulus fibrosus - a ring of fibrous tissue & fibrocartilage;
encircles the pulpy substance (nucleus pulposus) of an intervertebral disc
anuria - a daily urine output of less than 50 ml
anus - the distal end and outlet of the rectum
aorta - the main systemic trunk of the arterial system of the body;
emerges from the left ventricle
aortic injury - This is a dramatic injury because
of the potential morbidity and mortality of the condition and its
treatment. Typically this is seen when the mechanism of injury is rapid
deceleration, resulting in differential forces on the proximal descending
aorta between fixed and more mobile portions. Thus, the most common site
of injury is just beyond the ligamentum arteriosum. In those patients who
survive to be evaluated, the injury consists of a tear of the intima with
containment of the blood by the adventitia and surrounding tissue. A
periaortic hematoma results but usually there is no active bleeding. The
hallmark sign is a widened mediastinum seen on chest radiograph, related
to the adventitial hematoma. Diagnosis begins with a high index of
suspicion based on the mechanism of injury, and a chest radiograph is
obtained to identify alterations in the contour of the mediastinum and
overall widening of the mediastinum. CT scans of the chest may help to
delineate the changes seen on chest radiography, specifically hematoma
around the affected portions of the aorta. The gold standard for the
diagnosis, however, remains arterial angiography, usually directed at
outlining the entire ascending, transverse arch, and proximal descending
portions of the aorta. All of these areas are at risk for blunt
injury to the aorta.
Much has been written in recent years regarding
alternative methods of diagnosis including more sophisticated chest CT
scan techniques and the use of transesophageal echocardiography. In
general, the CT scan has not provided the resolution needed for many
surgeons to adequately localize the injury for subsequent treatment.
Transesophageal echocardiography results are very dependent on the skill
and experience of the operator. In addition, much of the transverse arch
of the aorta is not well visualized with this modality. However, these
tests can be valuable as screening methods or adjunctive imaging in cases
where angiography is delayed or the findings are not definitive.
Treatment of blunt aortic injuries is usually performed by
qualified trauma or thoracic surgeons. While the threat of rupture of the
hematoma is always present, temporizing measures include hemodynamic
monitoring and aggressive BP control, often aided by IV beta blockade.
With such methods, definitive treatment can be delayed for hours or days
if deemed necessary because of the patient’s condition or other injuries.
Recently, the use of endovascular techniques has been
expanded to include selective use for tears of the proximal descending
thoracic aorta. Briefly, these techniques involve the percutaneous
placement of intraluminal stents within the region of aortic aneurysms and
dissections as an alternative to operative graft replacement. The
morbidity of a transthoracic approach and the need for aortic cross
clamping is eliminated. This treatment is still considered highly
experimental but may become a viable option for trauma patients.
aperture - an opening or orifice
apex - the pointed end of a conical structure, such as the apex of
the heart
apgar score - a method for assessing the overall status of an
infant soon after birth; based on evaluation of heart rate, respiratory
effort, muscle tone, reflex irritability, and color
aphasia - loss of ability to express oneself properly through
speech, or loss of verbal communication
apnea - temporary cessation of breathing
apneustic area - portion of the respiratory center in the pons;
sends stimulatory nerve impulses to the inspiratory area to activate and
prolong inspiration and to inhibit expiration
apocrine gland - a type of gland in which the secretory products
gather at the free end of the secreting cell and are pinched off, along
with some of the cytoplasm, to become the secretion, as in the mammary
glands
aponeurosis - a sheet like tendon joining one muscle with another or
with bone
appendage - a structure attached to the body
appendicitis - inflammation of the vermiform appendix
appositional growth - growth due to surface deposition of material,
as in the growth in diameter of cartilage and bone; also called exogenous
growth
aqueduct - a canal or passage, especially for the conduction of a
liquid
aqueous humor - the watery fluid, similar in composition to cerebro-spinal
fluid, that fills the anterior cavity of the eye
arachnoid - the middle of the three coverings (meninges) of the
brain or spinal cord
arbor vitae - the treelike appearance of the white matter tracts of
the cerebellum when seen in midsagittal section; a series of branching
ridges within the cervix of the uterus
areflexia - absence of reflexes
areola - any tiny space in a tissue; the pigmented ring around the
nipple of the breast
arrector pili - smooth muscles attached to hairs; contraction pulls
the hairs into a more vertical position, resulting in goose bumps
arrhythmia - irregular heart rhythm; also called dysrhythmia
arteriogram - roentgenogram of an artery after injection of a radi-opaque
substance into the blood
arteriole - small, almost microscopic, artery that delivers blood
to a capillary
artery - a blood vessel that carries blood away from the heart
arthritis - inflammation of a joint
arthrocentesis - insertion of a needle into a synovial (joint)
cavity to remove a sample of synovial fluid, to relieve pressure, or to
inject anesthetic or medication
arthrology - the study or description of joints
arthroscopy - a procedure for examining the interior of a joint,
e.g., the knee, by inserting an arthroscope into a small incision; used to
determine extent of damage, to remove torn cartilage, to repair cruciate
ligaments, or to obtain samples for analysis
arthrosis - a joint or articulation
articular capsule - sleeve like structure around a synovial joint;
composed of a fibrous capsule and a synovial membrane
articulate - to join together as a joint to permit motion between
parts
articulation - a joint; a point of contact between bones, cartilage
and bones, or teeth and bones
arytenoid - ladle-shaped
ascites - accumulation of serous fluid in the peritoneal cavity
aseptic - free from any infectious or septic material
asphyxia - unconsciousness due to interference with the oxygen
supply of the blood
aspiration - inhalation of a foreign substance (water, food or
foreign body) into the bronchial tree; drainage of a substance in or out
by suction
astereognosis - inability to recognize objects or forms by touch
asthenia - lack or loss of strength; debility
astigmatism - irregularity of the lens or cornea of the eye causing
an image to be out of focus and producing faulty vision
astrocyte - a neuroglial cell having a star shape; supports neurons
in the brain and spinal cord and attaches neurons to blood vessels
ataxia - lack of muscular coordination; lack of precision
atelectasis - collapsed or airless state of all or part of the
lung; may be acute or chronic
atherosclerosis - a process in which fatty substances are deposited
in arterial walls in response to stimuli such as hypertension; following
endothelial damage, white cells adhering to the walls take up cholesterol,
etc., ultimately forming plaque that occludes the lumen
atresia - abnormal closure of a passage; abnormal absence of a
normal body opening
atrial fibrillation - asynchronous contraction of the atria;
results in the cessation of atrial pumping
atrial natriuretic factor - peptide hormone produced by the atria
of the heart in response to stretching; it inhibits production of
aldosterone and, thus, lowers blood pressure
atrioventricular bundle - portion of the heart's conduction system
beginning at the AV node, passing through the cardiac skeleton between the
atria and ventricles and into the interventricular septum where it splits
into right and left bundle branches; also called bundle of His
atrium - a superior chamber of the heart
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B -
Babinski sign - extension of the great toe, with or without
fanning of the other toes, in response to stimulation of the outer margin
of the sole of the foot; normal up to 1 1/2 years of age
Bainbridge reflex - the increased heart rate that follows increased
pressure or distension of the right atrium
barium swallow - an X-ray examination of the upper gastrointestinal
tract to evaluate for ulcers, tumors, & bleeding
baroreceptor - nerve cell capable of responding to changes in blood
pressure; also called a pressoreceptor
basal metabolic rate - the rate of metabolism measured under
standard or basal conditions
basilar membrane - a membrane in the cochlea of the inner ear that
separates the cochlear duct from the scala tympani and on which the spiral
organ (organ of Corti) rests
basophil - a type of white blood cell characterized by a pale
nucleus and large granules that stain readily with basic dyes
benign - not malignant; favorable for recovery; mild disease
beta cell - a cell in the pancreatic islets (islets of Langer-hans);
secretes insulin
bicuspid valve - atrioventricular (AV) valve on the left side of
the heart; also called the mitral valve
bifurcate - having two branches or divisions; forked
bilateral - pertaining to two sides of the body
bile - a secretion of the liver consisting of water, bile salts,
bile pigments, cholesterol, lecithin and several ions; it assumes a role
in emulsification of fats prior to their digestion
biliary calculi - gallstones formed by cholesterol crystallization
in bile
bilirubin - red pigment that is one of the end products of
hemoglobin breakdown in liver cells; it is excreted as a waste material in
the bile
bilirubinuria - presence of above-normal levels of bilirubin in
urine
biliverdin - a green pigment that is one of the first products of
hemoglobin breakdown in liver cells; it is converted to bilirubin or
excreted as a waste material in bile
biopsy - removal of tissue or other material from the living body
for examination, usually microscopic
blastocoel - the fluid-filled cavity within the blastocyst
blastocyst - in the development of an embryo, a hollow ball of
cells that consists of a blastocoel (the internal cavity), trophoblast
(outer cells), and inner cell mass
blastomere - one of the cells resulting from the cleavage of a
fertilized ovum
blastula - an early stage in the development of a zygote
blepharism - spasm of the eyelids; continuous blinking
Bohr effect - in an acid environment, oxygen dissociates more
readily from hemoglobin; hydrogen ions binding to hemoglobin alter its
structure and reduce its oxygen-carrying capacity
bolus - soft, rounded mass, usually food, that is swallowed
bony labyrinth - a series of cavities within the petrous portion of
the temporal bone forming the vestibule, cochlea, and semicircular canals
of the inner ear
brachial plexus - a network of nerve fibers of the anterior rami of
spinal nerves C5, C6, C7, C8 and T1; nerves emerging from the brachial
plexus supply the upper extremity
Broca's area - motor area of the brain in the frontal lobe;
translates thoughts into speech; also called the motor speech area
bronchi - branches of the respiratory passageway including primary
bronchi (divisions of the trachea), secondary/ lobar bronchi (to the lobes
of the lung) and tertiary/ segmental bronchi (to bronchopulmonary segments
of the lung)
bronchial asthma - usually allergic reaction characterized by
smooth muscle spasms in bronchi resulting in wheezing and difficult
breathing
bronchiectasis - a chronic disorder in which there is a loss of
normal tissue & expansion of lung air passages; characterized by difficult
breathing, coughing, expectoration of pus, and foul breath
bronchiole - branch of tertiary bronchus further subdividing into
terminal bronchioles (to lobules of lung), which divide into respiratory
bronchioles (to alveolar sacs)
bronchitis - inflammation of bronchi characterized by hypertrophy
and hyperplasia of seromucous glands and goblet cells that line the
bronchi, resulting in a productive cough
bronchogenic carcinoma - cancer originating in the bronchi
bronchogram - a roentgenogram of the bronchial tree
bronchography - technique for examining the bronchial tree in which
an opaque contrast medium is introduced into the trachea for distibution
to the bronchial branches; produces a bronchogram
bronchopulmonary segment - one of the smaller divisions of a lobe
of a lung supplied by its own branches of a bronchus
bronchoscope - an instrument used to examine the interior of the
bronchi of the lungs
bronchoscopy - visual examination of the interior of the trachea
and bronchi with a bronchoscope to biopsy a tumor, to clear an
obstruction, to take cultures, to stop bleeding, or to deliver drugs
bronchus - one of the two large branches of the trachea
buccal - pertaining to the cheek or mouth
bulbourethral gland - one of a pair of glands located inferior to
the prostate gland on either side of the urethra; it secretes an alkaline
fluid into the cavernous urethra; also called a Cowper's gland
bulimia - a disorder characterized by overeating, at least twice a
week, followed by purging by self-induced vomiting, strict dieting or
fasting, vigorous exercise, or use of laxatives
bullae - blisters beneath or within the epidermis
bunion - lateral deviation of the great toe; produces inflammation
and thickening of the bursa, bone spurs, and calluses
bursa - a sac or pouch of synovial fluid located at friction
points, especially about joints
bursitis - inflammation of a bursa
buttocks - the two fleshy masses on the posterior aspect of the
lower trunk, formed by the gluteal muscles
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C -
cachexia - a state of ill health
calcification - deposition of mineral salts, primarily
hydroxyapatite, in a framework formed by collagen fibers in which the
tissue hardens
calcitonin - hormone produced by the parafollicular cells of the
thyroid gland; it lowers calcium and phosphate levels of the blood by
inhibiting bone breakdown and accelerating calcium absorption by bones
calculus - a stone, or insoluble mass of crystallized salts or
other material, formed within the body, as in the gallbladder, the kidney,
or the urinary bladder
callus - a growth of new bone tissue in & around a fractured area,
ultimately replaced by mature bone; acquired, localized thickening
calmodulin - intracellular protein that binds with calcium ions and
activates or inhibits enzymes, many of which are protein kinases, to
elicit physiological responses of hormones
calorie - the standard LETTER of heat; the amount of heat necessary
to raise 1 g of water from 14 to 15 degrees C; the kilocalorie, used in
metabolic and nutritional studies, is the amount of heat necessary to
raise 1,000 g of water 1 degree C and is equal to 1,000 cal
calyx - any of the cuplike divisions of the kidney pelvis; plural,
calyces
canaliculus - a small channel or canal, as in bones, where they
connect lacunae; plural, canaliculi
cancellous - having a reticular or latticework structure, as in
spongy tissue of bone
canker sore - painful ulcer on the mucous membrane of the mouth; it
may result from an autoimmune response
capacitation - the functional changes that sperm undergo in the
female reproductive tract; these changes allow them to fertilize a
secondary oocyte
capillary - a microscopic blood vessel located between an arteriole
and venule through which materials can be exchanged between blood and body
cells
carbohydrate - organic compound containing carbon, hydrogen, and
oxygen in a particular amount and arrangement.
carcinoembryonic antigen - a glycoprotein secreted by normally
developing fetal tissue during the first or second trimester, after birth,
and in certain malignant and benign conditions
carcinogen - any substance that causes cancer
carcinoma - a malignant tumor consisting of epithelial cells
cardiac arrest - cessation of an effective heartbeat; the heart may
stop completely or undergo ventricular fibrillation
cardiac catheterization - introduction of a catheter into the heart
and/or its blood vessels to: measure pressure; assess left ventricular
function & cardiac output; measure blood flow & oxygen content; assess
valve & conduction system status; identify septal or valvular defects
cardiac tamponade - While this injury is more common in penetrating
trauma, blunt chest trauma also may result in rupture of a cardiac
structure. It may be of a degree that does not result in rapid and fatal
exsanguination immediately, but rather causes so much blood to accumulate
within the pericardium that it begins to exert pressure on the heart. The
most susceptible areas are the vena cava and atria, resulting in depressed
venous return to the heart and subsequent hemodynamic instability.
Classically the diagnosis can be made by Beck’s triad: increased jugular
venous distention (or elevated central venous pressure, if monitored),
muffled heart sounds, and hypotension. The heart sounds may be difficult
to hear in the emergency department. A globular appearance of the
pericardium on a chest radiograph also may be suggestive of this injury.
Initial treatment usually consists of some type of rapid evacuation of the
pericardial space, either via a pericardiocentesis or subxiphoid
pericardial window. Emergent thoracotomy, also known as a resuscitative
thoracotomy or emergency room thoracotomy, is classically performed
through the left anterolateral approach in the intercostal region in the
lower half of the chest. This allows access to the pericardium to relieve
tamponade. It may also allow open massage of the heart and clamping of the
descending thoracic aorta to try to maintain blood flow to the cerebral
region. Although its benefit has been described in penetrating chest
injuries, multiple other reports have shown its futility in blunt chest
cases. Experiences to date have found that victims who arrive pulseless
and unresponsive to all other measures have uniformly not responded to
emergency thoracotomy.
cardioacceleratory center - a group of neurons in the medulla from
which cardiac sympathetic nerves arise; nerve impulses along these nerves
release norepinephrine that increases the rate and force of the heartbeat
cardioinhibitory center - a group of neurons in the medulla from
which arise parasympathetic fibers that reach the heart via the vagus (X)
nerve; nerve impulses along these nerves release acetylcholine that
decreases the rate & force of the heartbeat
cardiology - the study of the heart and its associated diseases
cardiopulmonary resuscitation - CPR; technique employed to restore
life or consciousness to a person apparently dead or dying; includes
external respiration (exhaled air respiration) & external cardiac massage
cardiovascular center - groups of neurons scattered within the
medula that regulate heart rate, force of contraction, and blood vessel
diameter
carina - a ridge on the inside of the division of the right and
left primary bronchi
carotid body - receptor on or near the carotid sinus that responds
to alterations in blood levels of oxygen, carbon dioxide, and hydrogen
ions
carpus - a collective term for the eight bones of the wrist
cartilage - a type of connective tissue consisting of chondrocytes
in lacunae embedded in dense network of collagenous and elastic fibers in
a matrix of chondroitin sulfate
cartilaginous joint - a joint without a synovial (joint) cavity
where the articulating bones are held tightly together by cartilage,
allowing little or no movement
caruncle - a small, fleshy eminence, often abnormal
castration - the removal of the testes
catabolism - chemical reactions involving the break down of complex
organic compounds into simple ones with the release of energy
cataract - loss of transparency of the lens of the eye or its
capsule or both
catheter - a tube that can be inserted into a body cavity through a
canal or into a blood vessel; used to remove fluids, such as urine and
blood, and to introduce diagnostic materials or medication
cation - a positively charged ion; an example is a sodium ion
cauda equina - a tail like collection of roots of spinal nerves at
the inferior end of the spinal canal
caudal - pertaining to any tail like structure; inferior in position
cecum - blind pouch at the proximal end of the large intestine
below the terminal portion of the ileum
celiac - pertaining to the abdomen
cementum - calcified tissue covering the root of a tooth
centrioles - paired, cylindrical structures within a centrosome,
each consisting of a ring of microtubules; arranged at right angles to
each other; function in cell division to organize the spindle apparatus
centromere - the clear constricted portion of a chromosome where
the two chromatids are joined; serves as the point of attachment for the
chromosomal microtubules
centrosome - dense area of cytoplasm, near the nucleus of a cell,
containing a pair of centrioles
cephalic - pertaining to the head; superior in position
cerebellar peduncle - a bundle of nerve fibers connecting the
cerebellum with the brain stem
cerebellum - the portion of the brain lying posterior to the
medulla and pons, concerned with coordination of movements
cerebral aqueduct - a channel through the mid-brain connecting the
third and fourth ventricles and containing cerebrospinal fluid
cerebral palsy - a group of motor disorders resulting in muscular
uncoordination and loss of muscle control caused by damage to motor areas
of the brain (cerebral cortex, basal ganglia, cerebellum) during fetal
life, birth, or infancy
cerebrospinal fluid - a fluid produced in the choroid plexuses and
ependymal cells of the ventricles of the brain; it circulates in the
ventricles and the subarachnoid space around the brain and spinal cord
cerebrovascular accident - destruction of brain tissue (infarction)
resulting from disorders of blood vessels that supply the brain (also
called a stroke)
cerebrum - the two hemispheres of the forebrain, making up the
largest part of the brain
ceruminous gland - a modified sudoriferous (sweat) gland in the
external auditory meatus; it secretes cerumen (ear wax)
cervical dysplasia - change in the growth, number, and shape of
cervical cells of the uterus that, if severe, may progress to cancer
cervix - neck; any constricted portion of an organ, such as the
lower cylindrical part of the uterus
cesarean section - procedure in which a low, horizontal incision is
made through the abdominal wall and uterus for removal of the baby and
placenta; also called a C-section
chalazion - a small tumor of the eyelid
chemiosmosis - process by which energy released is used to generate
ATP when a substance moves along a gradient
chemonucleolysis - dissolution of the nucleus pulposus of an
intervertebral disc by injection of a proteolytic enzyme (chymopapain) to
relieve pressure and pain associated with a herniated (slipped) disc
chemoreceptor - receptor that detects the presence of chemicals;
e.g., outside the central nervous system on or near the carotid and aortic
bodies
chemotaxis - attraction by a chemical stimulus, e.g., phagocytes to
microbes
chemotherapy - the treatment of illness or disease by chemicals
chiasma - a crossing; especially the crossing of the optic (II)
nerve fibers
chiropractic - a system of treating disease by using one's hands to
manipulate body parts, mostly the vertebral column
chlamydia - organism causing a sexually transmitted disease
characterized by burning on urination, frequent and painful urination, and
low back pain; may spread to uterine (Fallopian) tubes in females
choana - a funnel-shaped structure; the posterior opening of the
nasal fossa, or internal nares
cholecystectomy - surgical removal of the gallbladder
cholesterol - classified as a lipid, the most abundant steroid in
animal tissues; located in cell membranes and used for synthesis of
steroid hormones and bile salts
cholinergic fiber - nerve ending that liberates acetylcholine at a
synapse
cholinesterase - an enzyme that hydrolyzes acetylcholine
chondrocyte - cell of mature cartilage
chondroitin sulfate - amorphous matrix material found outside of
cells
chordae tendineae - tendon like, fibrous cords that connect the
heart valves with the papillary muscles
chorion - the outermost fetal membrane; becomes the principle
embryonic portion of the placenta; serves a protective and nutritive
function
chorionic villus - fingerlike projection of the chorion; it grows
into the decidua basalis of the endometrium and contains fetal blood
vessels
choroid - one of the vascular coats of the eyeball
chromaffin cell - cell that has an affinity for chrome salts, owing
in part to the presence of the precursors of the neuro-transmitter
epinephrine; found, among other places in the adrenal medulla
chromatid - one of a pair of identical connected nucleoprotein
strands that are joined at the centromere and separate during cell
division, each becoming a chromosome of one of the two daughter cells
chromatin - threadlike mass of genetic material consisting
principally of DNA; it is present in the nucleus of a non-dividing or
interphase cell
chromatolysis - the breakdown of chromatophilic substance (Nissl
bodies) into finely granular masses in the cell body of a central or
peripheral neuron whose process (axon or dendrite) has been damaged
chromosome - one of the 46 small, dark-staining bodies that appear
in the nucleus of a human diploid (2n) cell during cell division
chronic - long-term or frequently recurring; applied to a disease
that is not acute
chyle - the milky fluid found in the lacteals of the small
intestine after digestion
chyme - the semi-fluid mixture of partly digested food and digestive
secretions found in the stomach and small intestine during digestion of a
meal
cicatrix - a scar left by a healed wound
ciliary body - one of the three portions of the vascular tunic of
the eyeball, the others being the choroid and the iris; includes the
ciliary muscle and the ciliary processes
cilium - a hair or hair like process projecting from a cell that may
be used to move the entire cell or to move substances along the surface of
the cell
circadian rhythm - a cycle of active and non-active periods in
organisms determined by internal mechanisms, repeating about every 24
hours
circumcision - surgical removal of the foreskin (prepuce), the fold
of skin over the glans penis
circumduction - a movement at a synovial joint in which the distal
end of a bone moves in a circle while the proximal end remains relatively
stable
circumvallate papilla - one of the circular projections that is
arranged in an inverted V-shaped row at the posterior portion of the
tongue; the largest of the elevations on the upper surface of the tongue
containing taste buds
cirrhosis - a liver disorder in which the parenchymal cells are
destroyed and replaced by connective tissue
cisterna chyli - the origin of the thoracic duct
climacteric - cessation of the reproductive function in the female
or diminution of testicular activity in the male
clitoris - female erectile organ located at the anterior junction
of the labia minora; it is homologous to the male penis
clone - a population of cells identical to itself
coagulation - process by which a blood clot is formed
coarctation of the aorta - a congenital condition in which the
aorta is too narrow; it results in reduced blood supply, increased
ventricular pumping, and high blood pressure
coccyx - the fused bones at the end of the vertebral column
cochlea - a winding, cone-shaped tube forming a portion of the
inner ear and containing the spiral organ (organ of Corti)
coitus - sexual intercourse; also called copulation
colitis - inflammation of the mucosa of the colon and rectum;
absorption of water and salts is reduced, producing watery, bloody feces,
and, in severe cases, dehydration and salt depletion; spasms of the
muscularis produce cramps
collagen - a protein that is the main organic constituent of
connective tissue
colliculus - a small elevation
colostomy - creating a surgical opening through the exterior
abdominal wall into the colon for the diversion of feces
colostrum - thin, cloudy fluid secreted by the mammary glands a few
days prior to or after delivery before true milk is secreted
colposcopy - direct examination of the vaginal & cervical mucosa
using a magnifying device; frequently the first procedure performed
following an abnormal Pap smear
coma - final stage of brain failure; it is characterized by total
unresponsiveness to all external stimuli
commissure - the angular junction of the eyelids at either corner
of the eyes
complement - a group of at least twenty proteins found in serum and
forming a component of nonspecific resistance and immunity by bringing
about cytolysis, inflammation, and opsonization
computed tomography (CT) - X-ray technique that provides a
cross-sectional image of any area of the body; also called computed axial
tomography (CAT)
concha - a scroll-like bone found in the skull; plural, conchae
concussion - a traumatic injury to the brain that produces no
visible bruising but may cause abrupt, temporary loss of conciousness
conductivity - ability to carry the effect of a stimulus from one
part of a cell to another; highly developed in nerve and muscle fibers
(cells)
congenital - present at the time of birth
conjunctiva - delicate membrane covering the eyeball and lining the
eyelids
conjunctivitis - inflammation of the conjunctiva, the delicate
membrane covering the eyeball & lining the eyelids
constipation - infrequent or difficult defecation resulting from
decreased intestinal motility
contraception - the prevention of conception or impregnation
with-out destroying fertility
contractility - ability of cells or parts of cells actively to
generate force leading to shortening and change of form for purposeful
movements; muscle fibers (cells) display a high degree of contractility
contralateral - on the opposite side; affecting the opposite side
of the body
contusion - condition in which tissue below the skin is damaged,
but the skin is not broken
conus medullaris - the tapered portion of the spinal cord below the
lumbar enlargement
convergence - arrangement in which synaptic end bulbs of more than
one presynaptic neuron terminate on one postsynaptic neuron; medial
movement of the two eye-balls so that both are directed at a close object
being viewed so that a single image is produced
convulsion - violent, involuntary, tetanic contractions of an
entire group of muscles
cor pulmonale (CP) - right ventricular hypertrophy from disorders
that bring about hypertension in pulmonary circulation
cornea - the nonvascular, transparent fibrous coat of the eye
through which the iris can be seen
corona - margin of the glans penis
coronary angiography - a procedure in which the severity and
location of blocked coronary arteries are visualized by injection of
contrast dyes or in which clot-dissolving drugs may be injected into
coronary arteries
coronary sinus - a wide venous channel on the posterior surface of
the heart that collects the blood from the coronary circulation and
returns it to the right atrium
corpora quadrigemina - the four small elevations (superior and
inferior colliculi) on the dorsal region of the midbrain concerned with
visual and auditory functions
corpus albicans - a white fibrous patch in the ovary that forms
after regression of the corpus luteum
corpus callosum - the great commissure of the brain connecting the
cerebral hemispheres
corpus luteum - a yellow endocrine gland in the ovary formed when a
follicle has discharged its secondary oocyte; secretes estrogens,
progesterone, and relaxin
corpus striatum - an area in the interior of each cerebral
hemisphere composed of the caudate and lentiform nuclei of the basal
ganglia and the white matter of the internal capsule, arranged in a
striated manner
cortex - an outer layer of an organ; the convoluted layer of gray
matter covering each cerebral hemisphere
costal cartilage - the hyaline cartilage that attaches each rib to
the sternum
cranial cavity - a subdivision of the dorsal body cavity; formed by
the cranial bones and containing the brain
craniosacral outflow - fibers of parasympathetic preganglionic
neurons; they have their cell bodies located in nuclei in the brain stem
and in the lateral gray matter of the sacral portion of the spinal cord
craniotomy - any operation on the skull, as for surgery on the
brain or for decompression of the fetal head in difficult labor
cranium - the portion of the skull that protects the brain and the
organs of sight, hearing, and balance; includes the frontal, parietal,
temporal, occipital, sphenoid, and ethmoid bones
creatine phosphate - high-energy molecule in skeletal muscle cells
that is used to generate ATP rapidly; on decomposition, creatine phosphate
breaks down into creatine, phosphate, and energy—the energy is used to
generate ATP from ADP
crenation - the shrinkage of red blood cells into knobbed, starry
forms when placed in a hypertonic solution
cretinism - severe congenital thyroid deficiency during childhood
leading to physical and mental retardation
crista - a crest or ridged structure; a small elevation in the
ampulla of each semicircular duct that serves as a receptor for dynamic
equilibrium
crus of penis - separated, tapered portion of the corpora cavernosa
penis; plural, crura
cryosurgery - the destruction of tissue by application of extreme
cold
cryptorchidism - the condition of having undescended testes
cupula - the mass of gelatinous material covering the hair cells of
a crista, a receptor in the ampulla of a semicircular canal that is
stimulated when the head moves
curvature - a nonangular deviation of a straight line, as in
greater and lesser curvatures of the stomach; abnormal curvatures of the
vertebral column include kyphosis, lordosis, and scoliosis
cutaneous - pertaining to the skin
cyanosis - reduced (unoxygenated) hemoglobin concentration in blood
of more than 5 g/dl; it results in a blue or dark purple discoloration
that is most easily seen in the nail beds and mucous membranes
cyst - a sac with a distinct connective tissue wall, containing a
fluid or other material
cystic duct - the duct that transports bile from the gallbladder to
the common bile duct
cystitis - an inflammation of the urinary bladder
cystoscope - instrument used to examine the inside of the urinary
bladder
cystoscopy - direct visual examination of the urinary tract (and
prostate gland in males as well) using a cystoscope to evaluate urinary
tract disorders & to remove tissue for biopsy, kidney stones, urinary
bladder tumors, & urine samples
cytochrome - one of a series of proteins with an iron-containing
(heme) group, capable of alternating between a reduced and an oxidized
form
cytokine - growth factor produced by activated lymphocytes and
other cells that acts as an autocrine or paracrine and has various roles
in immunity and blood cell development
cytokinesis - division of the cytoplasm
cytology - the study of cells
cytoplasm - substance that surrounds organelles and is located
within a cell's plasma membrane, external to its nucleus; also called
protoplasm
cytosol - semi-fluid portion of cytoplasm in which organelles and
inclusions are suspended and solutes are dissolved—also called
intracellular fluid
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D -
dartos - contractile tissue under the skin of the scrotum
debility - weakness of tonicity in functions or organs of the body
decibel (db) - a LETTER of measurement for relative sound intensity
(loudness)
decidua - that portion of the endometrium of the uterus (all but
the deepest layer) that is modified for pregnancy and shed after
childbirth
deciduous - falling off or being shed seasonally or at a particular
stage of development; in the body, referring to the first set of teeth
decubitus ulcer - tissue destruction due to a constant deficiency
of blood to tissues overlying a bony projection subjected to prolonged
pressure against an object like a bed, cast, or splint; also bedsore,
pressure sore, trophic ulcer
decussation - a crossing-over; usually refers to the crossing of
most of the fibers in the large motor tracts to opposite sides in the
medullary pyramids
deep fascia - a sheet of connective tissue wrapped around a muscle
to hold it in place
defecation - discharge of feces from the rectum
defibrillation - delivery of a very strong electrical current to
the heart in an attempt to stop ventricular fibrillation
degeneration - a change from a higher to a lower state; a breakdown
in structure
deglutition - the act of swallowing
dehydration - excessive water loss from the body or its parts
delirium - a transient disorder of abnormal cognition (perception,
thinking or memory) and disordered attention, accompanied by disturbance
of sleep-wake cycles and psychomotor behavior; also called acute
confusional state (ACS)
dementia - an organic mental disorder resulting in permanent or
progressive general loss of intellectual abilities (e.g., memory,
judgement, and abstract thinking) and changes in personality; most common
cause is Alzheimer's disease
demineralization - loss of calcium and phosphorus from bones
denaturation - disruption of the tertiary structures of a protein
by agents, such as heat, pH changes, or other physical or chemical
methods; as a result, the protein loses its physical and biological
properties
dendrite - a nerve cell process that carries a nerve impulse toward
the cell body
dendritic cell - one type of antigen-presenting cell with long
branchlike projections, for example, Langerhans cells in the epidermis
dens - tooth
dental caries - gradual demineralization of the enamel and dentin
of a tooth; it may invade the pulp and alveolar bone; also called tooth
decay
denticulate - finely toothed or serrated; characterized by a series
of small, pointed projections
dentin - osseus tissues of a tooth, enclosing the pulp cavity
dentition - the eruption of teeth; the number, shape and
arrangement of teeth
deoxyribonucleic acid/DNA - nucleic acid in the shape of a double
helix; constructed of nucleotides consisting of 1 of 4 nitrogenous bases
(adenine, cytosine, guanine, or thymine), deoxyribose, and a phosphate
group; the genetic information is encoded in the nucleotides
depolarization - in neurophysiology, the reduction of voltage
across a cell membrane; expressed as a movement toward less negative (more
positive) voltages on the interior side of the cell membrane
depression - movement in which a part of the body moves downward
dermatology - medical specialty dealing with diseases of the skin
dermatome - an instrument for incising the skin or cutting thin
transplants of skin; the cutaneous area developed from one embryonic
spinal cord segment and receiving most of its innervation from one spinal
nerve
dermis - a layer of dense connective tissue lying deep to the
epidermis; the true skin or corium
detritus - particulate matter produced by or remaining after the
wearing away or disintegration of a substance or tissue; scales, crusts,
or loosened skin
detrusor muscle - muscle in the wall of the urinary bladder
diabetes insipidus - condition caused by hyposecretion of
antidiuretic hormone (ADH) and characterized by thirst and by excretion of
large amounts of urine
diabetes mellitus - hereditary condition caused by hyposecretion of
insulin; characterized by hyperglycemia, increased urine production,
excessive thirst and excessive eating
diagnosis - distinguishing one disease from another or determining
the nature of a disease from signs and symptoms by inspection, palpation,
laboratory tests, and other means
dialysis - the process of separating small molecules from large by
the difference in their rates of diffusion through a selectively permeable
membrane
diapedesis - the passage of white blood cells through intact blood
vessel walls
diaphragm - partition separating one area from another, e.g., the
dome-shaped skeletal muscle between the thoracic and abdominal cavities;
or a dome-shaped structure that fits over the uterine cervix, usually with
a spermicide, to prevent conception
diaphragmatic injury - Diaphragmatic injury
typically results from the rapid increase in intra-abdominal pressure
related to an episode of blunt trauma with subsequent rupture of the
diaphragm. This is suspected based on the mechanisms of injury and
radiographic appearance.3,28 As opposed to the defects seen
with penetrating trauma, the defects in blunt trauma usually are larger
and more often result in immediate herniation of abdominal contents. When
the defect is small, herniation may occur over a period of weeks to
months. This gradual occurrence is related in part to the differential
between intrathoracic and intra-abdominal pressures.
The diagnosis may be difficult in part because the force
of injury is likely to result in multiple organ damage, which will command
the resuscitation team’s attention. The chest radiograph will often be
abnormal, showing opacification within the affected pleural cavity, air
fluid levels, and mediastinal shift. Compression of the lung may also
occur. The findings may be mistaken for primary lung collapse, pleural
fluid, or hematoma.
While rupture of the right diaphragm occurs in about one
third of cases, the liver appears to protect against significant organ
herniation into the right pleural space. Therefore, most cases seem to
involve the left side, and the stomach is the most common organ involved.
Thus, nasogastric tube placement can be helpful in making the diagnosis by
chest radiography alone. Barium studies of the GI tract are another
important diagnostic modality. It is important to keep diaphragmatic
rupture in mind when performing tube thoracostomy for a suspected
hematoma. Digital exploration of the pleural cavity prior to tube
placement may be valuable. Treatment for acute cases usually involves
laparotomy for reduction of the herniated contents, inspection for other
intra-abdominal injury, and diaphragm repair.
diaphysis - the shaft of a long bone
diarrhea - frequent defecation of liquid feces caused by increased
intestinal motility
diarthrosis - articulation in which opposing bones move freely, as
in a hinge joint
diastole - in the cardiac cycle, the phase of relaxation or
dilation of the heart muscle, especially, the ventricles
diastolic blood pressure - the force exerted by blood on arterial
walls during ventricular relaxation; the lowest blood pressure measured in
the large arteries, about 80 mm Hg under normal conditions for a young,
adult male
diencephalon - part of the brain consisting primarily of the
thalamus and the hypothalamus
differential - a white blood cell count that reports the number of
each kind of white blood cell in a sample of 100 cells
differentiation - the acquisition of specific functions different
from those of the original general type
diffusion - a passive process in which there is a net or greater
movement of molecules or ions from a region of high concentration to a
region of low concentration until equilibrium is reached
digestion - mechanical and chemical breakdown of food to simple
molecules that can be absorbed and used by body cells
dilate - to expand or swell
dilation and curettage - following dilation of the uterine cervix,
the uterine endometrium is scraped with a curette (spoon-shaped
instrument); also called a D and C
diploid - having the number of chromosomes characteristically found
in somatic cells of an organism; symbolized 2n
diplopia - double vision
dislocation - the displacement of a bone from a joint with tearing
of ligaments, tendons, and articular capsules; also called luxation
dissect - to separate tissues & parts of a cadaver (corpse) or an
organ for anatomical study
dissociation - the separation of inorganic acids, bases, and salts
into ions when dissolved in water; also called ionization
distal - farther from the attachment of an extremity to the trunk
or to a structure; farther from the point of origin
diuretic - chemical that inhibits sodium reabsorption, reduces
antidiuretic hormone (ADH) concentration, & increases urine volume by
inhibiting facultative reabsorption of water
diurnal - repeating daily; pertaining to daylight hours (opposite:
nocturnal)
divergence - an anatomical arrangement in which the synaptic end
bulbs of one presynaptic neuron terminate on several postsynaptic neurons
diverticulitis - inflammation of diverticula, saclike outpouchings
of the colonic wall, when the muscularis becomes weak
diverticulum - sac or pouch in the wall of a canal or organ,
especially in the colon
donor insemination - deposition of seminal fluid within the vagina
or cervix at a time during the menstrual cycle when pregnancy is likely;
may be homologous (husband's semen) or heterologous (donor's semen); also
called artificial insemination
dorsal ramus - a branch of a spinal nerve containing motor and
sensory fibers supplying the muscles, skin, and bones of the posterior
part of the head, neck, and trunk
dorsiflexion - bending the foot in the direction of the dorsum
(upper surface)
dropsy - a condition in which there is abnormal accumulation of
water in the tissues and cavities
ductus arteriosus - a small vessel connecting the pulmonary trunk
with the aorta; found only in the fetus
ductus epididymis - tightly coiled tube inside the epididymis,
distinguished into a head, body, and tail; it is the site where
spermatozoa under-go maturation
ductus (vas) deferens - duct that conveys spermatozoa from the
epididymis to the ejaculatory duct; also called the seminal duct
ductus venosus - a small vessel in the fetus that helps the
circulation bypass the liver
duodenal gland - gland in the submucosa of the duodenum that
secretes an alkaline mucus to protect the lining of the small intestine
from the action of enzymes & to help neutralize the acid in chyme; also
called Brunner's gland
duodenum - the first 25 cm (10 in.) of the small intestine
dura mater - outer membrane (meninx) covering the brain and spinal
cord
dynamic equilibrium - the maintenance of body position, mainly the
head, in response to sudden movements such as rotation
dysfunction - absence of complete normal function
dyslexia - impairment of the brain's ability to translate images
received from the eyes or ears into understandable language
dysmenorrhea - painful menstruation
dysphagia - difficulty in swallowing
dysplasia - change in the size, shape, and organization of cells
due to chronic irritation or inflammation; may revert to normal if stress
is removed or may progress to neoplasia
dyspnea - shortness of breath
dystocia - difficult labor due to such factors as pelvic
deformities, malpositioned fetus, and premature rupture of fetal membranes
dystrophia - progressive weakening of a muscle
dysuria - painful urination
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E -
echocardiogram - a procedure in which high frequency sound waves
directed at the heart are reflected back and the echoes are picked up by a
transducer and converted to an image
ectopic - out of the normal location
eczema - a skin rash characterized by itching, swelling,
blistering, oozing, and scaling of the skin
edema - an abnormal accumulation of interstitial fluid
effector - an organ of the body, either a muscle or a gland, that
responds to a motor neuron impulse
efferent arteriole - vessel of the renal vascular system that
transports blood from the glomerulus to the peritubular capillary
effusion - escape of fluid from the lymphatics or blood vessels
into a cavity or into tissues
ejaculation - reflex ejection of semen from the penis
ejaculatory duct - the tube that transports spermatozoa from the
ductus (vas) deferens to the prostatic urethra
elasticity - ability of tissue to return to its original shape
after contraction or extension
electrocardiogram - a recording of the electrical changes
accompanying the cardiac cycle that can be recorded on the body's surface;
may be resting, stress, or ambulatory
electroencephalogram /EEG - a recording of electrical impulses of
the brain to diagnose certain diseases (such as epilepsy), to furnish
information regarding sleep and wakefulness, and to confirm brain death
electrolyte - any compound that separates into ions when dissolved
in water and that is able to conduct electricity
electromyography - evaluation of the electrical activity of resting
or contracting muscle to find the causes of muscular weakness, paralysis,
involuntary twitching, & abnormal levels of muscle enzymes; also used as
part of biofeedback studies
eleidin - a translucent substance found in the stratum lucidum of
the epidermis
elevation - movement in which a part of the body moves upward
ellipsoidal joint - a synovial joint in which an oval-shaped
condyle of one bone fits into an elliptical cavity of another bone,
permitting side-to-side and back-and-forth movements; e.g., the wrist
joint between the radius and carpals; also called a condyloid joint
embolism - obstruction or closure of a vessel by an embolus
embolus - a blood clot, an air bubble, fat from broken bones, a
mass of bacteria, or other debris or foreign material transported by the
blood
embryo - the young of any organism in an early stage of
development; in humans, the developing organism from fertilization to the
end of the eighth week in utero
embryology - the study of development from the fertilized egg to
the end of the eighth week in utero
emesis - vomiting
emmetropia - the ideal optical condition of the eyes
emphysema - a swelling or inflation of air passages due to loss of
elasticity in the alveoli
emulsification - the dispersion of large fat globules into smaller
uniformly distributed particles in the presence of bile
enamel - the hard, white substance covering the crown of a tooth
endocardium - the layer of the heart wall composed of endothelium
and smooth muscle; it lines the inside of the heart and covers the valves
and tendons that hold the valves open
endochondral ossification - replacement of cartilage by bone; also
called intracartilaginous ossification
endocrine gland - any ductless gland that secretes hormones into
the blood
endocrinology - the science concerned with the structure and
functions of endocrine glands and the diagnosis and treatment of disorders
of the endocrine system
endocytosis - uptake into a cell of large molecules and particles
in which a segment of plasma membrane surrounds the substance, encloses
it, and brings it in; includes phagocytosis, pinocytosis, and
receptor-mediated endocytosis
endodontics - a branch of dentistry concerned with the prevention,
diagnosis, and treatment of diseases that affect the pulp, root,
periodontal ligament, and alveolar bone
endogenous - growing from or beginning within the organism
endolymph - the fluid within the membranous labyrinth of the inner
ear
endometriosis - the growth of endometrial tissue outside the uterus
endometrium - the mucous membrane lining the uterus
endomysium - an invagination of the perimysium separating each
individual muscle fiber (cell)
endoneurium - connective tissue wrapping around individual nerve
fibers (cells)
endoplasmic reticulum (ER) - network of channels that run through
the cytoplasm of a cell serving in intracellular transport, support,
storage, synthesis, and packaging of molecules; some portions may have
ribosomes attached (rough ER) & some lack ribosomes (smooth ER)
endorphin - a neuropeptide in the central nervous system that acts
to reduce pain
endoscope - an illuminated tube with lenses used to look inside
hollow organs such as the stomach (gastroscope) or the urinary bladder
(cystoscope)
endoscopy - visual examination of any cavity of the body using an
endoscope, an illuminated tube with lenses
endosteum - a membrane that lines the medullary cavity of bones,
consisting of osteoprogenitor cells and scattered osteoblasts
endothelium - a layer of simple squamous epithelium that lines the
cavities of the heart & the blood & lymphatic vessels
enkephalin - a peptide found in the central nervous system that
acts to relieve pain
enteroendocrine cell - stomach cell that secretes the hormone
gastrin
enterogastric reflex - reflex that inhibits gastric secretion;
initiated by food in the small intestine
enuresis - involuntary discharge of urine, complete or partial,
after age 3
enzyme - substance that affects the speed of chemical changes; an
organic catalyst, most often a protein
eosinophil - a type of white blood cell characterized by granular
cytoplasm readily stained by eosin
ependymal cells - neuroglial cells that line ventricles of the
brain and probably assist in circulation of cerebrospinal fluid (CSF);
also called ependymocytes
epicardium - the thin outer layer of the heart wall, composed of
serous tissue & mesothelium; also called the visceral pericardium
epidemic - a disease that occurs above the expected level among
individuals in a population
epidemiology - medical science concerned with the occurrence and
distribution of disease in human populations
epidermis - outermost, thinner layer of skin, composed of
stratified squamous epithelium
epididymis - comma-shaped organ lying along the posterior border of
the testis & containing the ductus epipidymis in which the sperm mature;
plural, epididymides
epidural space - a space between the spinal dura mater and the
vertebral canal containing loose connective tissue and a plexus of veins
epiglottis - a large, leaf-shaped peice of cartilage lying on top
of the larynx; its stem is attached to the thyroid cartilage and its leaf
portion is unattached and free to move up and down to cover the glottis
(vocal folds and rima glottidis)
epilepsy - neurological disorder that is characterized by short
periodic attacks of motor, sensory, or psychological malfunction
epimysium - fibrous connective tissue around muscles
epinephrine - hormone secreted by the adrenal medulla; it produces
actions similar to those that result from sympathetic stimulation; also
called adrenaline
epineurium - the outermost covering around the entire nerve
epiphyseal plate - a cartilaginous plate between the epiphysis &
the diaphysis; it is responsible for the lengthwise growth of long bones
epiphysis - the end of a long bone; it is usually larger in
diameter than the shaft (diaphysis)
episiotomy - a cut made with surgical scissors to avoid tears in
the perineum at the end of the second stage of labor
epistaxis - loss of blood from the nose due to trauma, infection,
allergy, neoplasm, & bleeding disorders; also called nosebleed
epithelial tissue - tissue that forms glands or the outer part of
the skin; it lines blood vessels, hollow organs, and passages that lead
from the body to the exterior
eponychium - a narrow band of stratum corneum at the proximal
border of a nail, extending from the nail margin; also called the cuticle
erection - the enlarged and stiffened state of the clitoris or the
penis, resulting from the engorgement of the spongy erectile tissue with
blood
eructation - forceful expulsion of gas from the stomach; also
called belching
erythema - skin redness/inflammation usually caused by engorgement
of the capillaries in the lower layers of skin
erythematosus - pertaining to redness or erythema
erythrocyte - red blood cell
erythropoiesis - formation of erythrocytes (red blood cells)
erythropoietin - a hormone formed from a plasma protein; it
stimulates erythrocyte (red blood cell) production
esophagus - hollow muscular tube connecting the pharynx and the
stomach
esophageal injury - Injury to the esophagus related
to blunt external trauma is usually quite rare. Injury may be the result
of rapid compression of the abdomen, which may raise pressures in the
stomach to such a degree that an intraluminal tear of the esophagus
results. Another mechanism is accelerated insufflation of pressured air
into the esophagus in an attempt to ventilate the patient. Given the force
of injury involved, other organs may be affected, particularly the
trachea, which may also be ruptured.
Clinically, the patient may complain of chest or abdominal
pain; later, signs of sepsis from contamination of the mediastinum and
pleura may be present. Chest radiographs may show widening of the
mediastinum, subcutaneous emphysema, pneumothorax, hydrothorax, or a
combination. Usually the lower esophagus is affected; rupture is therefore
into the left pleural cavity. Tube thoracostomy for drainage is often
performed. If the output is suggestive of gastric contents or the injury
is otherwise clinically suspected, a contrast study or endoscopy of the
upper GI tract is indicated to evaluate the patient for esophageal injury.
Treatment is usually surgical and should be performed early to minimize
contamination of mediastinum and pleura. Primary repair vs diversion will
depend on the condition of the esophagus, degree of contamination present,
and, in some cases, the length of time from injury to surgery.
estrogens - female sex hormones from the ovaries; they support
development/maintenance of female reproductive structures and secondary
sex characteristics, fluid and electrolyte balance, and protein anabolism;
e.g., beta-estradiol, estrone, and estriol
etiology - the study of the causes of disease, including theories
of origin & the organisms, if any, involved
euphoria - subjectively pleasant feeling of well-being marked by
confidence and assurance
eupnea - normal quiet breathing
euthanasia - the practice of ending a life in case of incurable
disease
eversion - the movement of the sole outward at the ankle joint
exacerbation - an increase in the severity of symptoms or of
disease
excitability - the ability of muscle tissue to receive and respond
to stimuli; the ability of nerve cells to respond to stimuli and to
convert them into nerve impulses
excrement - material cast out from the body as waste, especially
fecal matter
excretion - the process of eliminating waste products from a cell,
tissue, or the entire body; also, the products excreted
exocrine gland - a gland that secretes substances into ducts that
empty at covering or lining epithelium or directly onto a free surface
exocytosis - a process of discharging large cellular products;
particles are enclosed by Golgi membranes when synthesized; vesicles pinch
off from the Golgi complex & carry enclosed particles to the interior of
the cell membrane; fusion occurs & contents are discharged
exogenous - originating outside an organ or part
exon - a region of DNA that codes for synthesis of a protein
exophthalmic goiter - autoimmune disease that may result in
hypersecretion of thryoid hormones; it is characterized by protrusion of
the eyeballs (exophthalmos) and an enlarged thyroid (goiter); also called
Grave's disease
expiration - breathing out; expelling air out of the lungs into the
atmosphere; also called exhalation
expiratory reserve volume - the volume of air in excess of tidal
volume that can be exhaled forcibly; equal to about 1,200 ml
extensibility - ability of muscle tissue to be stretched when
pulled
extension - increase in the angle between two bones; restoring a
body part to its anatomical position after flexion
external auditory canal - curved tube in the temporal bone that
leads to the middle ear; also called the external auditory meatus
external nares - the external nostrils; the openings into the nasal
cavity on the exterior of the body
exteroceptor - a receptor adapted for the reception of stimuli from
outside the body
extracorporeal - the circulation of blood outside the body
extravasation - escape of fluid, especially of blood, lymph, or
serum, from a vessel into tissue spaces
extrinsic - of external origin
exudate - escaping fluid or semifluid material that oozes from a
space; it may contain serum, pus, & cellular debris
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F -
facilitated diffusion - diffusion in which a substance not
soluble by itself in lipids is transported across a selectively permeable
membrane by combining with a transporter (carrier) molecule
facilitation - process in which a nerve cell membrane is
partially depolarized by a subliminal stimulus so that a subsequent
subliminal stimulus can depolarize the membrane further to reach the
threshold of nerve impulse initiation
facultative reabsorption - absorption of water from distal
convoluted tubules and collecting tubules of nephrons in response to
antidiuretic hormone (ADH)
falciform ligament - a sheet of parietal peritoneum between the
two principal lobes of the liver; the ligamentum teres, or remnant of the
umbilical vein, lies within its folds
falx cerebelli - a small triangular process of the dura mater
attached to the occipital bone in the posterior cranial fossa and
projecting inward between the cerebellar hemispheres
fascia - fibrous membrane covering, supporting, & separating
muscles
fascicle - a small bundle or cluster, especially of nerve or muscle
fibers (cells); also called a fasciculus (plural, fasciculi)
fasciculation - involuntary brief twitch of a muscle, visible under
the skin and not associated with the movement of the affected muscle
fauces - the opening from the mouth into the pharynx
febrile - feverish; pertaining to a fever
feces - material discharged from the rectum and made up of
bacteria, excretions, and food residue; also called stool
fenestration - surgical opening made into the labyrinth of the ear
for some conditions of deafness
fertilization - penetration of a secondary oocyte by a spermatozoon
and subsequent union of the nuclei of the cells
fetus - latter stages of the developing young of an animal; in
humans, the developing organism in utero from the beginning of the third
month to birth
fibrillation - involuntary brief twitch of a muscle; visible under
the skin & not associated with movement of the affected muscle
fibrin - an insoluble protein that is essential to blood clotting;
formed from fibrinogen by the action of thrombin
fibrinogen - a high-molecular-weight protein in the blood plasma
that, by action of thrombin, is converted to fibrin
fibrinolysis - dissolution of a blood clot by action of a
proteolytic enzyme that converts insoluble fibrin into a soluble substance
fibroblast - large, flat cell that forms collagenous and elastic
fibers and intercellular substance of loose connnective tissue
fibrocyte - a mature fibroblast that no longer produces fibers or
intercellular substance in connective tissue
fibromyalgia - groups of common nonarticular rheumatic disorders
characterized by pain, tenderness, and stiffness of muscles, tendons, and
surrounding tissues; examples include lumbago and charleyhorse
fibroplasia - period of scar tissue formation
fibrosis - abnormal formation of fibrous tissue
fibrous joint - a joint that allows little or no movement, such as
a suture and a syndesmosis
filiform papilla - one of the conical projections that are
distributed in parallel rows over the anterior two-thirds of the tongue
and contain no taste buds
filtrate - fluid produced when blood is filtered by the
endothelial-capsular membrane of the nephron; any material that has passed
through a filter
filtration - passage of liquid through a filter or a membrane that
acts like a filter
filum terminale - nonnervous fibrous tissue of the spinal cord; it
extends inferiorly from the conus medullaris to the coccyx
fimbriae - fingerlike structures, especially the lateral ends of
the uterine (Fallopian) tubes
fissure - a groove, fold, or slit that may be normal or abnormal
fistula - abnormal passage between two organs or between an organ
cavity and the outside
flaccid - relaxed, flabby, or soft; lacking muscle tone
flagellum - hairlike, motile process on the extremity of a
bacterium or protozoan; plural, flagella
flail chest - This is the result of an injury of
the chest wall significant enough to include multiple ribs resulting in a
"free-floating" portion of the chest wall. Three major pathophysiologic
events occur because of this. The first is interruption of the normal
negative intrathoracic pressure needed to effect spontaneous ventilation
as a result of the paradoxical motion of the flail portion of the chest
wall. The more significant injury, however, is usually underlying
pulmonary contusion, which leads to hemorrhage and edema of the injured
lung. Finally, the amount of associated pain will often result in
splinting with subsequent hypoventilation. The immediate threat to life
depends on the amount of chest wall involved and the extent of the
contusion. Treatment is centered on an assessment of the degree of
pulmonary insufficiency with ventilator support as indicated. Rarely is
physical stabilization of the chest wall necessary.
flatus - air (gas) in the stomach or intestines, commonly used to
denote the passage of gas rectally
flexion - folding movement in which there is a decrease in the
angle between two bones
fluoroscope - an instrument for visual observation of the body by
means of X-ray
follicle - a small secretory sac or cavity
fontanel - a membrane-covered spot where bone formation is not yet
complete, especially between the cranial bones of an infant's skull
foramen - a passage or opening; a communication between two
cavities of an organ or a hole in a bone for passage of vessels or nerves
foramen ovale - opening in the fetal heart in the septum between
the right and left atria; hole in the greater wing of the sphenoid bone
that transmits the mandibular branch of the trigeminal (V) nerve
fornix - an arch or fold; a tract in the brain made up of
association fibers, connecting the hippocampus with the mamillary bodies;
a recess around the cervix of the uterus where it protrudes into the
vagina
fossa - a shallow depression or a furrow
fracture - any break in a bone
frenulum - small fold of mucous membrane that connects two parts
and limits movement
fulminate - to occur suddenly with great intensity
fundus - that part of a hollow organ farthest from the opening or
exit
fungiform papilla - a mushroomlike elevation on the upper surface
of the tongue, appearing as a red dot; papillae contain taste buds
furuncle - a boil; a painful nodule caused by bacterial infection
and inflammation of a hair follicle or sebaceous (oil) gland
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G -
gamete - a male or female reproductive cell; the spermatozoon or
ovum
ganglion - a group of nerve cell bodies that lie outside the
central nervous system; plural, ganglia
gangrene - death and rotting of a considerable mass of tissue; it
usually is caused by an interruption of blood supply, followed by
bacterial invasion by members of the genusClostridium
gastroenterology - the medical specialty that deals with the
structure, function, diagnosis, and treatment of diseases of the stomach
and intestines
gastrointestinal (GI) tract - a continuous tube running through the
ventral body cavity extending from the mouth to the anus; also called the
alimentary canal
gastroscopy - diagnostic procedure in which the interior of the
stomach is examined with a gastroscope to: detect lesions, biopsy lesions,
stop bleeding, and remove foreign objects
gastrulation - the various movements of groups of cells that lead
to the establishment of the primary germ layers in the embryo
gavage - feeding via a tube passed through the esophagus and into
the stomach
gene - biological LETTER of heredity; an ultramicroscopic,
self-reproducing DNA segment, located in a specific position on a
particular chromosome
genital herpes - a sexually-transmitted disease caused by type II
herpes simplex virus
genitalia - reproductive organs
genome - the complete gene complement of an organism
genotype - the total hereditary information carried by an
individual; the genetic makeup of an organism
geriatrics - the branch of medicine devoted to the medical problems
and care of elderly persons
germanitivum - the skin layers where new cells are germinated
germinal epithelium - a layer of epithelial cells that covers the
ovaries and lines the seminiferous tubules of the testes
gestation - the period of intrauterine fetal development
giantism - condition caused by hyper-secretion of human growth
hormone (hGH) during childhood, characterized by excessive bone growth and
body size; also called gigantism
gingivae - gums; they cover the alveolar processes of the mandible
and maxilla & extend slightly into each tooth socket
gingivitis - inflammation of the gums
glans penis - slightly enlarged region at the distal end of the
penis
glaucoma - eye disorder in which there is increased intraocular
pressure due to an excess of aqueous humor
glomerular capsule - double-walled globe at the proximal end of a
nephron; it encloses the glomerulus; also called Bowman's capsule
glomerulonephritis - inflammation of the glomeruli of the kidney;
it increases the permeability of the endothelial-capsular membrane and
permits blood cells and proteins to enter the filtrate; also called
Bright's disease
glomerulus - rounded mass of nerves or blood vessels, especially
the microscopic tuft of capillaries surrounded by the glomerular
(Bowman's) capsule of each kidney tubule
glottis - the vocal folds (true vocal cords) in the larynx and the
space between them (rima glottidis)
glucagon - a hormone produced by the alpha cells of the pancreas;
it increases the blood glucose level
glucocorticoids - a group of hormones of the adrenal cortex; they
influence glucose metabolism and are anti-inflammatory
gluconeogenesis - conversion of a molecule other than a
carbohydrate into glucose
glucose - a six-carbon sugar that also includes 12 hydrogen atoms
and six oxygen atoms; the major energy source for body cells
glycogen - a highly branched polymer of glucose containing
thousands of subLETTERs; it functions as a compact store of glucose
molecules in liver and muscle fibers (cells)
glycogenesis - the process by which many molecules of glucose
combine to form the polymer called glycogen
glycogenolysis - the process of converting glycogen to glucose
glycosuria - presence of glucose in the urine; may be temporary or
pathological; also called glucosuria
gnostic - pertaining to the faculties of perceiving and recognizing
goiter - a chronic enlargement of the thyroid gland
Golgi complex - cytoplasmic organelle consisting of four to eight
flattened channels, stacked on each other, with expanded areas at their
ends; functions in packaging secreted proteins, in lipid secretion, and in
carbohydrate synthesis
gomphosis - a fibrous joint in which a cone-shaped peg fits into a
socket
gonad - an organ that produces both gametes and hormones; the ovary
in the female and the testis in the male
gonadocorticoids - sex hormones secreted by the adrenal cortex
gonadotropic hormone - a pituitary hormone that regulates the
functions of the gonads
gonorrhea - infectious, sexually-transmitted disease caused by the
bacterium Neisseria gonorrhoeae and characterized by inflammation of the
urogenital mucosa, discharge of pus, and painful urination
gout - hereditary condition associated with excessive uric acid in
the blood; the acid crystallizes and deposits in joints, kidney, and soft
tissues
gray ramus communicans - a short nerve containing postganglionic
sympathetic fibers; the cell bodies of the fibers are in a sympathetic
chain ganglion, and the nonmyelinated axons run by way of the gray ramus
to a spinal nerve and then to the periphery to supply effectors
greater omentum - large fold in the serosa of the stomach; it hangs
down like an apron over the front of the intestines
groin - the depression between the thigh and the trunk; the
inguinal region
gustatory - pertaining to taste
gynecology - a branch of medicine dealing with study and treatment
of disorders of the female reproductive system
gynecomastia - excessive growth (benign) of male mammary glands due
to secretion of estrogens by an adrenal gland tumor (feminizing adenoma)
gyrus - one of the folds of the cerebral cortex of the brain;
plural, gyri; also called a convolution
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H -
h.c. somatomammotropin - hCS; a hormone produced by the chorion
of the placenta that may stimulate breast tissue for lactation
h. chorionic gonadotropin - hCG; a hormone produced by the chorion
of the placenta; it maintains the corpus luteum
Haldane effect - decreased carbon dioxide binding in the blood as a
result of increased oxygen-hemoglobin binding; oxyhemoglobin is more
acidic than unbound hemoglobin and, therefore, combines with less carbon
dioxide
hallucination - the sensory perception of something that does not
really exist in the world; a sensory experience created from within the
brain
haploid - having half the number of chromosomes normally found in
the somatic cells of an organism; characteristic of mature gametes
haustra - the sacculated elevations of the colon
Haversian system - the basic structural LETTER in adult compact
bone, consisting of a central (Haversian) canal with concentrically
arranged lamellae, lacunae, osteocytes, and canaliculi; also called an
osteon
heart murmur - one of a number of abnormal heart sounds; consists
of a flow noise that is heard before the normal lubb-dupp or that may mask
normal heart sounds
hematocrit (Hct) - percentage of blood made up of red blood cells;
usually calculated by centrifuging a blood sample in a graduated tube &
reading off the volume of red blood cells and total blood
hematology - the study of blood
hematopoiesis - blood cell production occurring in the red bone
marrow; also called hemopoiesis
hematuria - blood in the urine
hemiballismus - violent muscular restlessness of half of the body,
especially of the upper extremity
hemiplegia - a paralysis of the upper extremity, trunk, and lower
extremity on one side of the body
hemocytoblast - immature stem cell in bone marrow; it develops
along different lines into all the types of mature blood cells
hemodialysis - filtering blood while it is circulated outside the
body by means of an artificial device; substances are removed as a result
of their different rates of diffusion through a selectively permeable
membrane
hemodynamics - study of factors and forces that govern the flow of
blood through blood vessels
hemoglobin - molecule in red blood cells consisting of the protein
globin and the iron-containing red pigment heme and constituting about 33%
of the cells' volume; it is involved in the transport of oxygen and carbon
dioxide
hemolysis - escape of hemoglobin from the interior of red blood
cells into the surrounding medium; results from disruption of the
integrity of the cell membrane by toxins or drugs, by freezing or thawing,
or by hypotonic solutions
hemolytic disease - a hemolytic anemia of a newborn child; it
results from the destruction of the infant's red blood cells by antibodies
produced by the mother; usually involves antibodies due to Rh blood type
incompatibility; also called erythroblastosis fetalis
hemophilia - a hereditary blood disorder where there is a deficient
production of certain factors involved in blood clotting, resulting in
excessive bleeding into joints, deep tissues, and elsewhere
hemopoiesis - blood cell production occurring in the red marrow of
bones; also called hematopoiesis
hemoptysis - spitting of blood from the respiratory tract
hemorrhage - bleeding; escape of blood from blood vessels,
especially when it is profuse
hemorrhoids - dilated or varicosed blood vessels (usually veins) in
the anal region; also called piles
hemostasis - the stoppage of bleeding
hemothorax - Blood from a variety of sources may
accumulate in the pleural space. In most cases, the volume is too small to
be hemodynamically significant in terms of volume loss or compression of
the lung or mediastinum. Still, evacuation via tube thoracostomy is
generally recommended. This allows the physician to detect any persistent
bleeding into the pleural space and prevents the organization of the
hemothorax, which can later progress to a fibrothorax with resultant lung
entrapment.
hepatic - referring to the liver
hepatitis - inflammation of the liver due to an infectious agent,
drugs, or chemicals
hepatopancreatic ampulla - a small, raised area in the duodenum
where the combined common bile duct and main pancreatic duct empty into
the duodenum; also called the ampulla of Vater
hernia - protrusion or projection of an organ or part of an organ
through a membrane or a cavity wall, usually the abdominal cavity
herniated disc - rupture of intervertebral disc so that the nucleus
pulposus protrudes into the vertebral cavity; also called a slipped disc
heterocrine gland - any gland, such as the pancreas, which is both
endocrine and exocrine
heterozygous - possessing a pair of different genes on homologous
chromosomes for a particular hereditary characteristic
hiatus - an opening; a foramen
hilus - an area, depression, or pit where blood vessels and nerves
enter or leave an organ; also called a hilum
hirsutism - excessive growth of hair in females and children, due
to the conversion of vellus hairs into large terminal hairs; occurs in
response to higher-than-normal levels of androgens; the distribution is
similar to that in adult males
histamine - a substance found in many cells, particularly mast
cells, basophils, and platelets, and released when the cells are injured;
results in vasodilation, increased permeability of blood vessels,and
bronchiole constriction
histocompatibility testing - comparison of human leucocyte
associated (HLA) antigens between donor and recipient to determine the
degree of compatibility between the two; also called HLA antigen typing or
tissue typing
histology - microscopic study of the structure of tissues
hives - skin condition marked by reddened elevated patches that are
often itchy; may be caused by infections, trauma, medications, emotional
stress, certain foods or food additives
holocrine gland - type of gland in which the entire secreting cell,
containing its accumulated secretions, is included in the secretory
product of the gland, as in the sebaceous or oil glands
homeostasis - the condition in which the body's internal
environment remains relatively constant, within physiological limits
homologous - a correspondence of two organs in structure, position,
and origin
hormone - a secretion of an endocrine gland; it alters the
physiological activity of target cells in the body
humoral immunity - the component of immunity in which lymphocytes
(B cells) develop into plasma cells that produce antibodies to destroy
antigens; also called antibody-mediated immunity
hyaline membrane disease - a disease of newborn infants, especially
those who are premature, in which insufficient amounts of surfactant are
produced and breathing is labored; also called respiratory distress
syndrome (RDS) of the newborn
hyaluronic acid - viscous, amorphous extra-cellular material; it
binds cells together, lubricates joints, and maintains the shape of the
eyeballs
hyaluronidase - enzyme that breaks down hyaluronic acid, increasing
the permeability of connective tissues by dissolving the substances that
hold body cells together
hydrocele - a fluid-containing sac or tumor; specifically, a
collection of fluid formed in the space along the spermatic cord and in
the scrotum
hydrocephalus - abnormal accumulation of cerebrospinal fluid on the
brain
hydrophobia - rabies; a condition characterized by severe muscle
spasms when attempting to drink water; also, an abnormal fear of water
hymen - a thin fold of vascularized mucous membrane at the vaginal
orifice
hyperbaric oxygenation - using a hyperbaric chamber to raise oxygen
levels in blood to treat anaerobic (tetanus and gangrene) bacterial
infections; also used to treat carbon monoxide poisoning
hypercalcemia - an excess of calcium in the blood
hypercapnia - an abnormal increase in the amount of carbon dioxide
in the blood
hyperemia - an excess of blood in an area or part of the body
hyperextension - continuation of extension beyond the anatomical
position, as in bending the head backward
hyperglycemia - elevated blood sugar level
hypermetropia - condition in which visual images are focused behind
the retina with resulting defective vision of near objects; farsightedness
hyperphosphatemia - an abnormally high level of phosphate in the
blood
hyperplasia - an abnormal increase in the numer of normal cells in
a tissue or organ, increasing its size
hyperpolarization - increase in the internal negativity across a
cell membrane, thus increasing the voltage and moving it farther away from
the threshold value
hypersecretion - overactivity of glands resulting in excessive
secretion
hypersensitivity - overreaction to an allergen, leading to
pathological changes in tissues; also called allergy
hypertension - high blood pressure
hyperthermia - elevated body temperature
hypertonia - increased muscle tone that is expressed as spasticity
or rigidity
hypertonic - having an osmotic pressure greater than that of the
solution with which it is compared
hypertrophy - excessive enlargement or overgrowth of tissue without
cell division
hyperventilation - a rate of respiration higher than that required
to maintain normal level of plasma PCO2
hypervitaminosis - an excess of one or more vitamins
hypocalcemia - lower than normal levels of calcium in the blood
hypochloremia - deficiency of chloride in the blood
hypoglycemia - abnormally low concentration of blood glucose; can
result from excess insulin (injected or secreted)
hypokalemia - deficiency of potassium in the blood
hypomagnesemia - deficiency of magnesium in the blood
hyponatremia - deficiency of sodium in the blood
hyponychium - the epithelium of the nail bed, particularly the
posterior part
hypophosphatemia - an abnormally low level of phosphate in the
blood
hypophyseal pouch - a fold of ectoderm in the stomodeal (mouth)
roof, from which the adenohypophysis (anterior lobe) of the pituitary
gland develops embryologically
hypophysis - pituitary gland
hypoplasia - defective (decreased) tissue development
hyposecretion - underactivity of glands resulting in decreased
secretion
hypospadias - displaced urethral opening; in the male, it may be on
the underside of the penis, at the penoscrotal junction, between the
scrotal folds, or in the perineum; in the female, the urethra opens into
the vagina
hypothalamic-hypophyseal tract - a bundle of nerve processes made
up of fibers that have cell bodies in the hypothalamus but release
neurosecretions in the posterior pituitary gland or neurohypophysis
hypothalamus - portion of the diencephalon that lies beneath the
thalamus and forms the floor and part of the wall of the third ventricle
hypothermia - lowering body temperature below 35 C (95 F) degrees;
in surgical procedures, it refers to deliberate cooling of the body to
slow metabolism and reduce tissue oxygen needs
hypotonia - state of decreased or lost muscle tone in which muscles
appear flaccid
hypotonic - having an osmotic pressure lower than that of another
solution with which it is compared
hypoventilation - a rate of respiration lower than that required to
maintain the normal level of plasma PCO2
hypovolemic shock - shock characterized by decreased intravascular
volume resulting from blood loss; may occur because of acute hemorrhage or
other excessive fluid loss
hypoxia - lack of adequate oxygen at the tissue level
hysterectomy - the surgical removal of the uterus
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I -
ileocecal sphincter - a fold of mucous membrane that guards the
opening from the ileum into the large intestine; also called ileocecal
valve
ileum - the terminal portion of the small intestine
immunity - state of being resistant to injury, particularly by
poisons, foreign proteins, and invading parasites, due to the presence of
antibodies
immunogenicity - the ability of an antigen to stimulate antibody
production
immunoglobulin (Ig) - an antibody synthesized by plasma cells
(derived from B lymphocytes) in response to the introduction of antigen;
immunoglobulins are divided into 5 kinds (IgG, IgM, IgA, IgD, IgE), based
primarily on the larger protein component present in the immunoglobulin
immunology - a branch of science dealing with the responses of
the body when it is challenged by antigens
immunosuppression - inhibition of the immune response
immunotherapy - an attempt to induce the immune system to mount an
attack against cancer cells by administration of antibodies or nonspecific
immune stimulants
imperforate - abnormally closed
impetigo - a contagious skin disorder characterized by pustular
eruptions
implantation - insertion of a tissue or a part into the body;
attachment of the blastocyst to the lining of the uterus 7-8 days after
fertilization
impotence - weakness; inability to copulate; failure to maintain an
erection long enough for sexual intercourse
in utero - within the uterus
in vitro - literally, in glass; outside the living body and in an
artificial environment such as a laboratory test tube
in vivo - in the living body
incontinence - inability to retain urine, semen, or feces, through
loss of sphincter control
infarction - the presence of a localized area of necrotic tissue,
produced by inadequate oxygenation of the tissue
infection - invasion and multiplication of microorganisms in body
tissues; may be inapparent or be characterized by cellular injury
infectious mononucleosis - contagious disease caused by the
Epstein-Barr virus (EBV) and characterized by elevated mononucleocyte and
lymphocyte counts, fever, sore throat, stiff neck, cough, and malaise
inferior vena cava (IVC) - the large vein that collects blood from
those parts of the body inferior to the heart and returns it to the right
atrium
inflammation - a localized, protective response to tissue injury
designed to destroy, dilute, or wall off the infecting agent or injured
tissue; characterized by redness, pain, heat, swelling, and occasional
loss of function
inflammatory bowel d. - 1) Crohn's disease (GI tract inflammation,
especially the distal ileum/proximal colon, which may extend from the
mucosa through the serosa) or 2) ulcerative colitis (GI tract
inflammation, usually limited to the large intestine and accompanied by
rectal bleeding)
infraspinous - below a spine; specifically the fossa located
beneath the scapular spine
infundibulum - the stalk-like structure that attaches the pituitary
gland (hypophysis) to the hypothalamus of the brain; the funnel-shaped,
open, distal end of the uterine (Fallopian) tube
ingestion - taking in of food, liquids, or drugs, by mouth
inguinal - pertaining to the groin
inorganic compound - any compound that usually lacks carbon, is
usually small, and contains ionic bonds; examples include water as well as
many acids, bases, and salts
insertion - manner or place of attachment of a muscle to the
bone(s) that it moves
insomnia - difficulty falling asleep as well as, usually, frequent
awakening
inspiration - the act of drawing air into the lungs
insula - triangular area of cerebral cortex that lies deep within
the lateral cerebral fissure, under the parietal, frontal, & temporal
lobes: it cannot be seen in an external view of the brain; also called the
island or isle of Reil
insulin - a hormone produced by the beta cells of the pancreas; it
decreases the blood glucose level
integrin - the receptor on a plasma membrane that interacts with an
adhesion protein found in intercellular material and in blood
integumentary - relating to the skin
intercalated disc - irregular transverse thickening of sarcolemma
that contains: 1) desmosomes holding the cardiac muscle fibers (cells)
together and 2) gap junctions that aid in the conduction of muscle action
potentials
intercostal nerve - a nerve supplying a muscle located between the
ribs
interferon (IFN) - one of the proteins (alpha, beta, gamma),
naturally produced by virus-infected cells; it induces uninfected cells to
synthesize antiviral proteins that inhibit intracellular viral replication
in uninfected cells; synthesized artificially via recombinant DNA methods
interphase - the period of the cell's life cycle during which all
processes except division are occuring; period between two mitotic
divisions; also called metabolic phase
interstitial endocrinocyte - cell located in the connective tissue
between semi-niferous tubules in mature testis; secretes testosterone;
also called an interstitial cell of Leydig
interventricular foramen - the narrow, oval opening through which
the lateral ventricles of the brain commmunicate with the third ventricle;
also called the foramen of Monro
intervertebral disc - the pad of fibrocartilage located between the
bodies of two adjacent vertebrae
intracellular fluid (ICF) - fluid located within cells
intrafusal fibers - three to ten specialized muscle fibers (cells),
enclosed partly by a connective tissue capsule that is filled with lymph;
these fibers compose the muscle spindles
intramembranous ossif.... - method of bone formation in which bone
is formed directly in membranous tissue
intraocular pressure (IOP) - the pressure in the eyeball, produced
mainly by aqueous humor
intrinsic - of internal origin; e.g., the intrinsic factor, a
muco-protein that is formed by gastric mucosa and is necessary for the
absorption of vitamin B12
intron - region of DNA that does not code for the synthesis of a
protein
intubation - insertion of a tube through the nose or mouth into the
larynx and trachea to allow entrance of air or to dilate a stricture
intussesception - the infolding (invagination) of one part of the
intestine within another segment
invagination - an infolding of the wall of a cavity into the cavity
itself
inversion - the movement of the sole inward at the ankle joint
ion - a charged particle or group of particles; formed usually when
a substance, such as salt, dissolves and dissociates
ipsilateral - on the same side; affecting the same side of the body
irritable bowel syndrome - stress-induced disease of the GI tract;
cramping and pain accompany alternating diarrhea and constipation; stool
may contain excess mucus; flatulence, nausea, and loss of appetite may
occur; also called irritable colon or spastic colon
ischemia - the lack of sufficient blood to a part due to
obstruction of circulation
isotonic - having equal tension or tone; having equal osmotic
pressure between two different solutions or two elements in a solution
isotope - chemical element that has the same atomic number as
another but has a different atomic weight; radioactive isotopes change
into other elements with emission of certain types of radiation
isovolumetric contraction - the period of time, about 0.05 sec,
between the start of ventricular systole and opening of the semilunar
valves; there is ventricular contraction, but no emptying, & there is a
rapid rise in ventricular pressure
isthmus - a narrow strip of tissue or narrow passage connecting two
larger parts
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J -
jaundice - condition characterized by yellowness in skin, whites
of the eyes, mucous membranes, and body fluids; results from buildup of
bilirubin
jejunum - the middle portion of the small intestine
joint kinesthetic receptor - a proprioceptive receptor located in a
joint, stimulated by joint movement
juxtaglomerular apparatus (JGA) - the macula densa (distal tubule
cells adjacent to an afferent and efferent arteriole) & juxtaglomerular
cells (modified cells of the afferent &, sometimes, efferent arteriole);
secretes renin when blood pressure starts to fall
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K -
karyotype - an arrangement of chromosomes by shape, size, and
position of centromeres
keratin - an insoluble protein found in the hair, nails, and other
keratinized tissues of the epidermis
keratinocyte - the most numerous of the epidermal cells that
function in keratin production
keratohyalin - a compound involved in the formation of keratin
keratosis - formation of a hardened growth of tissue
ketone bodies - substances such as acetone, acetoacetic acid, and
beta-hydroxybutyric acid, produced primarily during excessive fat
metabolism
ketosis - abnormal condition marked by excessive production of
ketone bodies
kidney - one of the paired reddish organs located in the lumbar
region; they regulate composition and volume of blood and produce urine
kilocalorie (kcal) - amount of heat required to raise the
temperature of 1000 grams of water 1 C degree; the LETTER used to express
the heating value of foods and to measure metabolic rate
kinesiology - the study of movement of body parts
kinesthesia - ability to perceive extent, direction, or weight of
movement; muscle sense
Korotkoff sounds - the various sounds that are heard while taking
blood pressure
kyphosis - exaggeration of the thoracic curve of the vertebral
column, leading to a round-shouldered or hunchback appearance
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L -
labia majora - two longitudinal folds of skin extending downward
and backward from the mons pubis of the female
labia minora - two small folds of mucous membrane lying medial to
the labia majora of the female
labial frenulum - the medial fold of mucous membrane between the
inner surface of the lip and the gums
labium - a lip; a liplike structure; plural, labia
labyrinth - an intricate communicating passageway, especially in
the internal ear
labyrinthine disease - malfunction of the internal ear
characterized by deafness, tinnitus, vertigo, nausea, and vomiting
laceration - wound or irregular area of the skin
lacrimal - pertaining to tears
lactation - the secretion and ejection of milk by the mammary
glands
lacteal - one of many lymphatic vessels in the intestinal villi;
they absorb fat molecules from digested food
lacuna - a small, hollow space, such as those in which the
osteoblasts lie within bones; plural, lacunae
lambdoidal suture - the line of union between the parietal bones
and the occipital bone in the skull; sometimes contains sutural (Wormian)
bones
lamellae - concentric rings found in compact bone
lamina - a thin, flattened layer or membrane, as the flattened part
on either side of the arch of a vertebra; plural, laminae
lamina propria - the connective tissue layer of a mucous membrane
lanugo - fine downy hairs that cover the fetus
laparoscopy - insertion of a laparoscope through an abdominal
incision to: view abdominal and pelvic viscera, remove fluids or tissues
for biopsy, drain ovarian cysts, cut adhesions, stop bleeding, and perform
tubal ligation
laryngitis - an inflammation of the mucous membrane lining the
larynx
laryngopharynx - the inferior portion of the pharynx, extending
downward from the level of the hyoid bone to divide posteriorly into the
esophagus & anteriorly into the larynx
laryngoscope - instrument for examining the larynx
laryngotracheal bud - outgrowth of foregut endoderm from which the
respiratory system develops
larynx - the voice box, a short passageway that connects the
pharynx with the trachea
lateral - farther from the midline of the body or a structure
lesion - any localized, abnormal change in tissue formation
lesser omentum - the fold of peritoneum that extends from the liver
to the lesser curvature of the stomach & the commencement of the duodenum
lethargy - a condition of drowsiness or indifference
leukemia - a malignant disease of the blood-forming tissues with
acute overproduction and accumulation of immature leucocytes, many of
which fail to reach maturity, or with chronic accumulation of mature
lymphocytes because they do not die at the end of a normal lifespan
leukocyte - a white blood cell
leukocytosis - an increase in the number of white blood cells,
characteristic of many infections and other disorders
leukopenia - a decrease in the number of white blood cells below
5,000 per cubic millimeter
leukoplakia - a disorder in which there are white patches in the
mucous membranes of the tongue, gums, and cheeks
libido - the sexual drive, conscious or unconscious
ligament - dense, regularly-arranged connective tissue attaching
bone to bone
ligand - a chemical in interstitial fluid, usually in a
concentration lower than that in cells
lingual frenulum - a fold of mucous membrane that connects the
tongue to the floor of the mouth
lipase - a fat-splitting enzyme
lipogenesis - synthesis of lipids from glucose or amino acids by
the cells in the liver
lipoma - a fatty tissue tumor, usually benign
lipoprotein - a protein containing lipid; some made in the liver
bind cholesterol & triglycerides to raise their solubility in blood; high
levels of LDL's (low-density) are risk factors for atherosclerosis & high
levels of HDL's (high-density) are protective against it
lithotripsy - a noninvasive procedure in which shock waves
generated by an instrument called a lithotriptor are used to pulverize
kidney stones or gallstones
lobe - any curved or rounded projection of a structure
locus coeruleus - a cluster of neurons in the brain stem where
norepinephrine (NE) is concentrated
lordosis - exaggeration of the lumbar curve of the vertebral column
lumbar - region of the back and side between the ribs and pelvis;
loin
lumen - the space within a tubular structure such as a blood vessel
or the intestine
lunula - the moon-shaped, white area at the base of a nail
luteinizing hormone (LH) - adenohypophysal hormone which, in
females, stimulates ovulation and progesterone secretion by the corpus
luteum and readies the mammary glands for milk production; in males, it
stimulates testosterone secretion by the testes
lymph - fluid confined in lymphatic vessels & flowing through the
lymphatic system to be returned to the blood
lymphangiography - a procedure in which lymphatic vessels and lymph
organs are filled with a radiopaque substance to be X-rayed
lymphatic vessel - a large vessel that collects lymph from lymph
capillaries & converges with other lymphatic vessels to form the thoracic
and right lymphatic ducts
lymphocyte - a type of white blood cell, found in lymph nodes,
associated with the immune system
lymphokines - powerful proteins secreted by T lymphocytes; they
stimulate the various activities of B and T cells in immune responses
lysosome - organelle in the cytoplasm of a cell, enclosed by a
single membrane and containing powerful digestive enzymes
lysozyme - bactericidal enzyme found in tears, saliva, and
perspiration
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M -
macrophage - a phagocytic cell derived from a monocyte; may be
fixed or wandering
macula - discolored spot or colored area; a small, thickened region
on the wall of the utricle and saccule, that serves as a receptor for
static equilibrium
macula lutea - a yellow spot in the center of the retina
malaise - discomfort, uneasiness, & indisposition, often indicative
of infection
malignant - referring to diseases that tend to become worse and
cause death, especially the invasion and spreading of cancer
malignant melanoma - a usually dark, malignant tumor of the skin;
contains melanin
malnutrition - state of poor nutrition that may be due to
inadequate food intake, imbalance of nutrients, malabsoption of nutrients,
inappropriate distribution of nutrients, increased nutrient requirements,
increased nutrient losses, or overnutrition
mammary gland - a modified sudoriferous (sweat) gland of the
female; it secretes milk for nourishment of the young
mammillary bodies - two small rounded bodies posterior to the tuber
cinereum, involved in reflexes related to the sense of smell
mammography - procedure for imaging the breasts (xeromammography or
film-screen mammography) to evaluate for breast disease or to screen for
breast cancer
Marfan syndrome - inherited disorder that results in connective
tissue abnormalities, especially in the skeleton, eyes, and cardiovascular
system
marrow - soft, spongelike material in the cavities within bone; red
marrow produces blood cells; yellow marrow is formed mainly of fatty
tissue and has no blood-producing function
massive hemothorax - Large amounts of blood
accumulated within the pleural cavity will cause hypovolemia and
hypotension. Sources of bleeding may include lung parenchyma, great
vessels, or chest wall vessels such as the intercostal artery. The
presentation is shock associated with absent breath sounds on the affected
side(s). Dullness to percussion may also be present, although this finding
is difficult to elicit in most resuscitation settings. Treatment consists
of rapid evacuation with large pleural chest tubes. Once the initial
accumulation of blood is evacuated, continued blood output from the chest
tube is monitored. The most important treatment during the resuscitative
period is rapid volume replacement. Definitive therapy requiring
thoracotomy is usually undertaken if the rate of chest tube output is >
100 mL every 30 min. Usually this is performed by a trauma or thoracic
surgeon under controlled conditions in the operating room.
mastectomy - surgical removal of breast tissue
mastication - chewing
meatus - a passage or opening, especially in the external portion
of a canal
mechanoreceptor - receptor that detects mechanical deformation of
the receptor itself or adjacent cells; stimuli so detected include those
related to touch, pressure, vibration, proprioception, hearing,
equilibrium, and blood pressure
medial - nearer the midline of the body or a structure
medial lemniscus - a flat band of myelinated nerve fibers that
extends through the medulla, pons, and midbrain; it terminates on the same
side in the thalamus; sensory neurons in this tract transmit impulses for
proprioception, fine touch, pressure, and vibration sensations
median aperture - one of the three openings in the roof of the
fourth ventricle through which cerebrospinal fluid enters the subarachnoid
space of the brain and spinal cord; also called the foramen of Magendie
mediastinum - a broad, median partition, actually a mass of tissue
found between the pleurae of the lungs; it extends from the sternum to the
vertebral column
medulla - an inner layer of an organ, such as the medulla of the
kidneys
medulla oblongata - the most inferior part of the brain stem
medullary cavity - space within the diaphysis of a mature bone; it
contains yellow marrow; also called the marrow cavity
medullary rhythmicity area - portion of the respiratory center in
the medulla that controls the basic rhythm of respiration
meiosis - the type of cell division restricted to sex-cell
production; involving two successive nuclear divisions, it results in
daughter cells with the haploid (n) number of chromosomes
melanin - a dark (black, brown, or yellow) pigment found in some
parts of the body, such as the skin
melanoblast - a precursor cell in the epidermis that gives rise to
melanocytes, cells that produce melanin
melanocyte - a pigmented cell located between or beneath cells of
the deepest layer of the epidermis; synthesizes melanin
melatonin - a hormone secreted by the pineal gland; may inhibit
reproductive activities
membranous labyrinth - portion of the labyrinth of the inner ear
that is located inside the bony labyrinth and separated from it by the
perilymph; made up of the membranous semi-circular canals, the saccule and
utricle, and the cochlear duct
menarche - beginning of the menstrual cycles
Meniere's syndrome - a type of labyrinthine disease characterized
by fluctuating loss of hearing, vertigo, and tinnitus; due to an increased
amount of endolymph that enlarges the labyrinth
meninges - three membranes covering the brain and spinal cord;
include the dura mater, the arachnoid, and the pia mater; singular, meninx
meningitis - an inflammation of the meninges, most commonly the pia
mater & the arachnoid
menopause - termination of menstrual cycles
menstrual cycle - a series of changes in the endometrium of a
nonpregnant female; with each cycle, the lining is thickened and matured
and is capable of supporting development of a fertilized ovum
menstruation - the periodic discharge of blood, tissue fluid,
mucus, and epithelial cells form the uterus; it usually lasts for 5 days;
it is caused by a sudden reduction in the levels of estrogens and
progesterone; also called the menstrual phase or menses
merocrine gland - secretory cell that remains intact throughout the
process of formation and discharge of the secretory products; e.g., the
salivary and pancreatic glands
mesenchyme - an embryonic connective tissue from which all other
connective tissues arise
mesentery - fold of peritoneum attaching the small intestine to the
posterior abdominal wall
mesocolon - fold of peritoneum attaching the colon to the posterior
abdominal wall
mesothelium - a layer of simple squamous epithelium that lines
serous cavities
mesovarium - a short fold of peritoneum that attaches an ovary to
the broad ligament of the uterus
metabolism - the sum total of all bio-chemical reactions that occur
within an organism, including synthetic (anabolic) reactions as well as
decomposition (catabolic) reactions
metacarpus - a collective term for the five bones making up the
palm of the hand
metaphase - second stage of mitosis in which chromatid pairs line
up on the equatorial plane of the cell
metaphysis - growing portion of a bone
metaplasia - the transformation of one cell into another
metarteriole - blood vessel that emerges from an arteriole,
traverses a capillary network, and empties into a venule
metastasis - the spread of cancer to the surrounding tissues
(local) or to other body sites (distant)
metatarsus - a collective term for the five bones located in the
foot between the tarsals and the phalanges
micelle - spherical aggregate of bile salts that dissolves fatty
acids and monoglycerides so that they can be transported into small
intestinal epithelial cells
microcephalus - an abnormally small head; premature closing of the
anterior fontanel so that the brain has insufficient room for growth,
resulting in mental retardation
microfilament - rodlike cytoplasmic structure about 6nm in
diameter; composes contractile LETTERs in muscle fibers (cells) and
provides support, shape, and movement in nonmuscle cells
microglia - neuroglial cells that carry on phagocytosis; also
called brain macrophages
microphage - any granular leucocyte that carries on phagocytosis,
especially neutrophils and eosinophils
microtomography - a procedure that combines the principles of
electron microscopy and computed tomography to produce highly magnified,
three-dimensional images of living cells
microtrabeculae - three-dimensional mesh-work of fine filaments,
ca. 10-15 nm in diameter, that hold together microfilaments, microtubules,
and intermediate filaments constituting the microtrabecular lattice
microtubule - a cylindrical cytoplasmic structure, ranging in
diameter from 18-30 nm and consisting of the protein tubulin; provides
support, structure, and transportation
microvilli - the microscopic, fingerlike projections of cell
membranes of small intestinal cells; they increase surface area for
absorption
micturition - the act of expelling urine from the urinary bladder;
also called urination
mineralocorticoids - a group of hormones of the adrenal cortex;
they affect mineral and water balance
mitochondrion - a double-membrane bounded organelle that plays a
central role in production of ATP; known as the powerhouse of the cell
mitosis - division of the cell nucleus involving distribution of
two sets of replicated chromosomes into separate nuclei; ensures that each
daughter nucleus has the same number and kind of chromosomes as the
original parent nucleus
mitral stenosis - a narrowing of the mitral valve by scar formation
or a congenital defect
Mittelschmerz - abdominopelvic pain that correlates with the time
of release of a secondary oocyte from the ovary
modality - any of the specific sensory entities, such as vision,
smell, or taste
modiolus - central pillar or column of the cochlea
molecule - the chemical combination of two or more atoms
monocyte - a type of white blood cell characterized by agranular
cytoplasm; the largest of the leucocytes
mons pubis - the rounded, fatty prominence over the symphysis
pubis, covered by coarse pubic hair
morbid - diseased; pertaining to disease
morula - a solid mass of cells produced by successive cleavages of
a fertilized ovum a few days after fertilization
mucin - a protein found in mucus
mucosa - a membrane that lines a body cavity opening to the
exterior; also called mucous membrane
mucous cell - a unicellular gland that secretes mucus; also called
a goblet cell
multiple sclerosis - progressive destruction of myelin sheaths of
neurons in the central nervous system, short-circuiting conduction
pathways
muscarinic receptor - a receptor found on all effectors innervated
by parasympathetic (& on some innervated by sympathetic) postganglionic
axons; so named because the actions of acetylcholine (Ach) on such
receptors are similar to those produced by application of muscarine
muscular dystrophies - several inherited muscle-destroying
diseases, characterized by degeneration of the individual muscle fibers
(cells), which leads to progressive atrophy of the skeletal muscle
muscularis - a muscular layer (coat or tunic) of an organ
muscularis mucosae - a thin layer of smooth muscle fibers (cells)
located in the outermost layer of the mucosa of the gastrointestinal tract
underlying the lamina propria of the mucosa
mutation - any chage in the sequence of bases in the DNA molecule
resulting in a permanent alteration in some heritable characteristic
myasthenia gravis - weakness of skeletal muscles caused by
antibodies directed against acetylcholine receptors; results in inhibition
of muscle contraction
myelin sheath - a white, phospholipid, segmented covering, formed
by neurolemmocytes (Schwann cells), around the axons and the dendrites of
many peripheral neurons
myelography - introduction of a contrast medium into the
subarachnoid space of the spinal cord to demonstrate tumors or herniated
(slipped) discs within or near the spinal cord
myocardial contusion - Myocardial contusion is
usually a result of blunt blows to the anterior portion of the chest, and
there is potential for injury to the underlying myocardium. The diagnosis
of myocardial contusion can often be problematic. The clinician should
focus on the clinical picture, which will depend largely on the type and
extent of injury. Major sequelae include regional wall motion
abnormalities and depressed cardiac function not unlike that seen with
myocardial infarction. Injured areas may also serve as a nidus for rhythm
disturbances. A pericardial effusion may occur, as can early or late
pericarditis. In more severe cases, intracardiac injury such as
ventricular or valvar rupture may be seen. Rather than relying on rigid
criteria, the diagnosis hinges on a strong index of suspicion and specific
tests for the potential sequelae: monitoring the ECG for the presence of
arrhythmias; measuring cardiac enzymes, which may demonstrate myocardial
injury; and using ultrasound to detect any wall motion abnormalities or
intracardiac injury. Accumulation of pericardial fluid may also be
assessed by echocardiography. Treatment is based on the findings. In
most cases, therapy is supportive and is often analogous to management
after myocardial infarction.
myocardial infarction - gross necrosis of myocardial tissue due to
interrupted blood supply; also called a heart attack
myocardium - the middle layer of the heart wall, made up of cardiac
muscle, composing the bulk of the heart, and lying between the epicardium
and the endocardium
myofibril - threadlike structure, running longitudinally through a
muscle fiber (cell) and consisting mainly of thick myofilaments (myosin)
and thin myofilaments (actin, troponin, tropomyosin)
myoglobin - the oxygen-binding conjugated protein present in the
sarcoplasm of muscle fibers (cells); contributes the red color to muscle
myogram - the record or tracing produced by a myograph, the
apparatus that measures and records the effects of muscular contractions
myology - the study of muscles
myometrium - the smooth muscle layer of the uterus
myopia - defect in vision so that objects can be seen clearly only
when very close to the eyes; nearsightedness
myosin - the contractile protein making up the thick myofilaments
of muscle fibers (cells)
myotonia - continuous muscle spasm; increased muscular irritability
and tendency to contract, and lessened ability to relax
myxedema - condition caused by hypothyroidism during the adult
years, characterized by swelling of facial tissues
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N -
nail matrix - the part of the nail beneath the body and root
from which the nail is produced
narcosis - an unconscious state due to physical or chemical
factors that depress neuronal excitability
nasal septum - vertical partition separating the nasal cavity
into left and right sides; of bone (perpendicular plate of ethmoid and
vomer) and cartilage, covered with a mucous membrane
nasolacrimal duct - a canal that transports the lacrimal
secretion (tears) from the nasolacrimal sac into the nose
nasopharynx - the uppermost portion of the pharynx, lying
posterior to the nose & extending down to the soft palate
nausea - discomfort characterized by loss of appetite and
sensation of impending vomiting
nebulization - administration of medication to selected portions of
the respiratory tract by droplets suspended in air
necrosis - death of a cell or group of cells as a result of disease
or injury
neonatal - pertaining to the first 4 weeks after birth
neoplasm - a new growth that may be benign or malignant
nephritis - inflammation of the kidney
nephron - the functional LETTER of the kidney
nephrotic syndrome - a condition in which the endothelial-capsular
membrane leaks, allowing large amounts of protein to escape into the urine
neuralgia - attacks of pain along the entire course or branch of a
peripheral sensory nerve
neuritis - an inflammation of a single nerve, two or more nerves in
separate areas, or many nerves simultaneously
neuroeffector junction - collective term for neuromuscular and
neuroglandular junctions
neurofibral node - a space (along a myelinated nerve fiber) between
the individual neurolemmocytes (Schwann cells) that form the myelin
sheath; also called the node of Ranvier
neurofibril - one of the delicate threads that forms a complicated
network in the cytoplasm of the cell body and processes of a neuron
neuroglandular junction - area of contact between a motor neuron
and a gland
neuroglia - nervous system cells specialized to perform connective
tissue functions; in the CNS, include astrocytes, oligodendrocytes,
microglia, & ependyma; in the PNS, include neurolemmocytes (Schwann cells)
& ganglion satellite cells; also called glial cells
neurohypophyseal bud - an outgrowth of ectoderm located on the
floor of the embryonic hypothalamus; it gives rise to the neurohypophysis
(posterior lobe) of the pituitary gland
neurohypophysis - the posterior lobe of the pituitary gland
neurolemma - the peripheral, nucleated cytoplasmic layer of the
neurolemmocyte (Schwann cell); also called sheath of Schwann
neurology - the branch of science that deals with the normal
functioning and disorders of the nervous system
neuromuscular junction - an area of contact between the axon
terminal of a motor neuron and the underlying sarcolemma of a muscle fiber
(cell); also called a myoneural junction
neuron - a nerve cell, consisting of a cell body, dendrites and
axon(s)
neuropeptide - molecule of two to about 40 amino acids that occurs
naturally in the brain and acts primarily to modulate responses associated
with neurotransmitters; examples are enkephalins and endorphins
neurophysin - small protein that aids in transport, storage, and
subsequent release of oxytocin (OT) and antidiuretic hormone (ADH)
neurosecretory cell - cell in the paraventricular or supraoptic
nucleus of the hypothalamus that produces oxytocin (OT) or antidiuretic
hormone (ADH) that will be released subsequently from axonal endings in
the neurohypophysis
neurosyphilis - form of the tertiary stage of syphilis in which
various types of nervous tissue are attacked by bacteria and degenerate
neutrophil - a type of white blood cell characterized by granular
cytoplasm and staining equally readily with acid or basic dyes
nicotinic receptor - a receptor found on both parasympathetic and
sympathetic postganglionic neurons; so named because actions of
acetylcholine (ACh) in such receptors are similar to those produced by
nicotine application
nociceptor - a free (naked) nerve ending that detects pain
Node of Ranvier - a space, along a myelinated nerve fiber, between
the adjacent neurolemmocytes (Schwann cells) that form the myelin sheath
and the neurolemma; also called neurofibral node
nondisjunction - failure of sister chromatids or homologous
chromosomes to separate properly during anaphase of mitosis (or equatorial
division of meiosis) or reductional division of meiosis; both pass to the
same daughter cell
norepinephrine (NE) - hormone secreted in small amounts by the
adrenal medulla; produces actions similar to those resulting from
stimulation of the sympathetic nervous system, where it is the transmitter
substance for the postganglionic neurons; also called noradrenaline
notochord - flexible rod of embyronic tissue that lies where the
future vertebral column will develop
nuclease - enzyme that breaks nucleotides into pentoses and
nitrogenous bases; examples are ribonuclease and deoxyribonuclease
nucleic acid - organic compound that is a long polymer of
nucleotides, each containing a pentose sugar, a phosphate group and one of
five possible nitrogenous bases (adenine, cytosine, guanine, thymine, or
uracil)
nucleolus - a nonmembranous spherical body within the nucleus;
composed of protein, DNA, and RNA; it functions in the synthesis and
storage of ribosomal RNA
nucleosome - the elementary structural subLETTER of a chromosome;
it consists of histones and DNA
nucleus - spherical or oval organelle of a cell that contains the
hereditary factors called genes; a cluster of unmyelinated nerve cell
bodies in the CNS; the central portion of an atom, made up of protons and
neutrons
nucleus cuneatus - a group of nerve cells in the inferior portion
of the medulla in which fibers of the fasciculus cuneatus terminate
nucleus gracilis - a group of nerve cells in the inferior portion
of the medulla in which fibers of the fasciculus gracilis terminate
nucleus pulposus - a soft, pulpy, highly elastic substance in the
center of an intervertebral disc, a remnant of the notochord
nystagmus - rapid, involuntary, rhythmic movement of the eye-balls;
horizontal, rotary, or vertical
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O -
obesity - body weight 10-20 % over a desirable standard as a
result of excessive fat accumulation; types include hypertrophic
(adult-onset) and hyperplastic (lifelong)
obstetrics - the specialized branch of medicine that deals with
pregnancy, labor, and the period of time immediately following delivery
obturator - anything that obstructs or closes a cavity or
opening
occlusion - the act of closure or state of being closed
occult - concealed or hidden from view, as, for example, occult
blood in stools
olfactory - pertaining to smell
oligodendrocyte - a neuroglial cell that supports neurons &
produces a phospholipid myelin sheath around neuronal axons in the central
nervous system
oligospermia - deficiency of spermatozoa in the semen
oliguria - a daily urinary output usually less than 250 ml
oncogene - a gene that has the ability to transform a normal cell
into a cancerous cell
oncology - the study of tumors
oogenesis - formation and development of the ovum
oophorectomy - the surgical removal of the ovaries
open pneumothorax - refers to an opening in the
chest wall large enough to disrupt the negative intrathoracic pressure
required for spontaneous ventilation. Initial treatment may include
positive pressure ventilation and/or rapid covering of the open wound with
evacuation of the pleural space via tube thoracostomy. For chest
trauma cases, large-bore (> 32F) tubes are recommended for better
evacuation of blood and other fluids. For related reasons, tubes are
usually positioned posteriorly, in a dependent position for the supine
patient.
ophthalmic - pertaining to the eye
ophthalmologist - physician who specializes in the diagnosis and
treatment of eye disorders with drugs, surgery, and corrective lenses
ophthalmology - the study of the structure, function, and diseases
of the eye
ophthalmoscopy - examination of the interior fundus of the eyeball
to detect retinal changes associated with hypertension, diabetes mellitus,
atherosclerosis, and increased intracranial pressure
opsin - the glycoprotein portion of a photopigment
opsonization - action of some antibodies that renders bacteria and
other foreign cells more susceptible to phagocytosis; also called immune
adherence
optic chiasma - crossing point of the optic (II) nerves, anterior
to the pituitary gland
optician - a technician who fits, adjusts, & dispenses corrective
lenses on prescription of an optometrist or an ophthalmologist
optometrist - specialist with a doctorate degree in optometry who
is licensed to examine & test the eyes and to treat visual defects by
prescribing corrective lenses
ora serrata - the irregular margin of the retina, lying internal
and slightly posterior to the junction of the choroid and ciliary body
oral cholecystogram - X-ray examination of the gallbladder to
evaluate for the presence of gallstones, inflammation, and tumors
orbit - the bony, pyramid-shaped cavity of the skull housing the
eyeball
organelle - structure inside a cell having characteristic
morphology, specialized to perform a specific function in cellular
activities
organic compound - compound that always contains carbon and
hydrogen and has the atoms held together by covalent bonds; examples
include carbohydrates, lipids, proteins, and nucleic acids (DNA and RNA)
organism - a total living form; one individual
orgasm - sensory and motor events involved in ejaculation for the
male and in involuntary contraction of the perineal muscles for the female
at the climax of sexual intercourse
orifice - any aperture or opening
origin - the place of attachment of a muscle to the more stationary
bone at a joint, or the end opposite the insertion
oropharynx - the second portion of the pharynx, lying posterior to
the mouth and extending from the soft palate down to the hyoid bone
orthopedics - a branch of medicine dealing with preservation and
restoration of the skeletal system, articulations, and related structures
orthopnea - dyspnea (discomfort in breathing) occuring when in the
horizontal position
osmoreceptor - hypothalamic receptor that is sensitive to changes
in blood osmotic pressure and that, in response to high osmotic pressure
(low water concentration), causes the synthesis and release of
antidiuretic hormone
osmosis - the net movement of water molecules through a selectively
permeable membrane from an area of high water concentration to an area of
lower water concentration until an equilibrium condition is achieved
osseus - bony
ossicle - a small bone, as those in the middle ear (incus, malleus,
stapes)
ossification - the formation of bone; also called osteogenesis
osteoblast - cell formed from an osteo-progenitor cell; it
participates in bone formation by secreting some organic components and
inorganic salts
osteoclast - a large multinuclear cell that develops from a
monocyte & destroys or resorbs bone tissue
osteocyte - a mature bone cell that maintains the daily activities
of bone tissue
osteogenic layer - the inner layer of the periosteum, containing
cells responsible for forming new bone during growth and repair
osteology - the study of bones
osteomalacia - deficiency of vitamin D in adults causing
demineralization and softening of the bones
osteomyelitis - inflammation of bone marrow or of both the bone and
marrow
osteoporosis - age-related disorder characterized by decreased bone
mass and increased susceptibility to fractures; may result from decreased
levels of estrogens
osteoprogenitor cell - a stem cell derived from mesenchyme, having
mitotic potential and ability to differentiate into an osteoblast
otalgia - pain in the ear; earache
otic - pertaining to the ear
otitis media - acute infection of the middle ear, characterized by
pain, malaise, fever, and an inflamed tympanic membrane that is subject to
rupture
otolith - a particle of calcium carbonate embedded in the otolithic
membrane; it functions in maintaining static equilibrium
otolithic membrane - a thick, gelatinous, glycoprotein layer,
located directly over the hair cells of the macula in the saccule and
utricle of the inner ear
otorhinolaryngology - the branch of medicine that deals with
diagnosis and treatment of diseases of the ears, nose, and throat
ovarian follicle - a general name for oocytes (immature ova),
regardless of their stage of development, along with their surrounding
epithelial cells
ovary - female gonad; it produces ova and hormones (estrogens,
progesterone, and relaxin)
ovulation - the rupture of a vesicular ovarian (Graafian) follicle,
with discharge of a secondary oocyte into the pelvic cavity
ovum - the female reproductive or germ cell; an egg cell
oxidation - the removal of electrons and hydrogen ions from (or,
less commonly, the addition of oxygen to) a molecule; it results in
decreasing the molecule's energy content; glucose oxidation in the body is
also called cellular respiration
oxyhemoglobin (HbO2) - hemoglobin combined with oxygen
oxytocin (OT) - hormone secreted by neurosecretory cells in the
paraventricular (mainly) & supraoptic nuclei of the hypothalamus;
stimulates contraction of both smooth muscle fibers in the uterus &
contractile cells around mammary ducts
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P -
Pacinian corpuscle - oval pressure receptor located in
subcutaneous tissue and consisting of concentric layers of connective
tissue wrapped around an afferent nerve fiber; also called a lamellated
corpuscle
Paget's disease - disorder characterized by a greatly
accelerated remodeling process; osteoclastic resorption is massive and new
bone formation by osteoblasts is extensive, resulting in irregular
thickening and softening of the bones
palate - the horizontal structure separating the oral and the
nasal cavities; the roof of the mouth
palliative - serving to relieve or alleviate without curing
palpate - to examine by touch; to feel
palpitation - a fluttering of the heart or an abnormal rate or
rhythm of the heart
pancreas - a soft, oblong organ lying along the greater curvature
of the stomach and connected by a duct to the duodenum; it has both
exocrine (pancreatic juice) and endocrine (insulin, glucagon, and
somatostatin) secretions
pancreatic duct - a single large tube, LETTERing with the common
bile duct from the liver and the gallbladder and draining pancreatic juice
into the duodenum at the hepatopancreatic ampulla (ampulla of Vater); also
called the duct of Wirsung
Papanicolaou test - a cytological staining test for detection and
diagnosis of premalignant/malignant conditions of the female genital
tract; epithelial cells scraped from the tract are smeared, fixed,
stained, and examined microscopically; also called a Pap smear
papilla - a small nipple-shaped projection or elevation
paracrine - local hormone, such as histamine, that acts on
neighboring cells
paralysis - loss or impairment of motor function due to a lesion of
nervous or muscular origin
paranasal sinus - a mucus-lined air cavity in a skull bone;
communicates with the nasal cavity; the paranasal sinuses are located in
the frontal, maxillary, ethmoid, and spenoid bones
paraplegia - paralysis of both lower extremities
parasympathetic division - one subdivision of the autonomic nervous
system; preganglionic cell bodies are in brain stem nuclei & lateral gray
matter of the sacral spinal cord; it is concerned with activities
conserving/restoring body energy; also called the craniosacral division
parathyroid gland - one of four small endocrine glands, embedded on
the posterior surfaces of the lateral lobes of the thyroid gland
paraurethral gland - mucous gland embedded in the wall of the
urethra; its duct opens on either side of the urethral orifice; also
called Skene's gland
parenchyma - the functional parts of any organ, as opposed to
tissue that forms its stroma or framework
parenteral - situated or occurring outside the intestines;
referring to introduction of substances into the body other than by way of
the intestines, such as intradermal, subcutaneous, intramuscular,
intravenous, or intraspinal
parietal pleura - the outer layer of serous pleural membrane;
encloses & protects the lungs; the layer that is attached to the wall of
the pleural cavity
parotid gland - one of the paired salivary glands located inferior
and anterior to the ears; connected to the oral cavity via a duct
(Stensen's) that opens on the inside of the cheek opposite the upper
second molar tooth
paroxysm - a sudden periodic attack or recurrence of symptoms of a
disease
parturition - the act of giving birth to young; childbirth;
delivery
patellar reflex - the extension of the leg by contraction of the
quadriceps femoris muscle in response to tapping on the patellar ligament;
also called the knee jerk
pathogen - any disease-producing organism
pathogenesis - the development of disease or a morbid or
pathological state
pathological - pertaining to or caused by disease
pectinate muscles - projecting muscle bundles of the anterior
atrial walls and lining of the auricles
pectoral - pertaining to the chest or breast
pediatrician - a physician specializing in the care and treatment
of children and their illnesses
pedicel - a footlike structure, as on podocytes of a glomerulus
pelvic cavity - inferior portion of the abdominopelvic cavity,
containing the urinary bladder, sigmoid colon, rectum, and internal female
and male reproductive structures
pelvic splanchnic nerves - preganglionic parasympathetic fibers
from the levels of S2, S3, and S4 that supply the urinary bladder,
reproductive organs, and the descending and sigmoid colon and rectum
pelvimetry - measurement of the size of the inlet and outlet of the
birth canal
penis - the male copulatory organ, used to introduce spermatozoa
into the vagina of the female
percussion - act of striking (percussing) an underlying part of the
body using short, sharp blows; aids in diagnosing the part by the quality
of the sound produced
pericardial cavity - small potential space between the visceral and
parietal layers of the serous pericardium; contains pericardial fluid
pericardium - a loose-fitting membrane that encloses the heart; it
consists of an outer fibrous layer and an inner serous layer
perichrondrium - the membrane that covers cartilage
perikaryon - the nerve cell body; it contains the nucleus and other
organelles
perilymph - fluid contained between the bony and membranous
labyrinths of the inner ear
perimetrium - the serosa of the uterus
perimysium - an invagination of the epimysium, dividing muscles
into bundles
perineum - the pelvic floor; the space between the anus and the
scrotum in the male and between the anus and the vulva in the female
perineurium - connective tissue wrapping around fascicles in a
nerve
periodontal disease - a collective term for conditions
characterized by degeneration of gingivae, alveolar bone, periodontal
ligament, and cementum
periosteum - membrane that covers bone and consists of connective
tissue, osteoprogenitor cells, and osteoblasts; it is essential for bone
growth, repair, and nutrition
peripheral - located on the outer part or a surface of the body
periphery - outer part or a surface of the body; part away from the
center
peristalsis - successive muscular contractions along the wall of a
hollow, muscular structure
peritoneum - largest serous membrane of the body; it lines the
abdominal cavity and covers the viscera
peritonitis - inflammation of the peritoneum
permissive effect - an hormonal interaction in which target cell
response to one hormone is enhanced by prior or simultaneous exposure to
(an)other hormone(s); endometrial maturation by progesterone, following an
exposure to estrogen, is an example
pernicious - fatal
peroxisome - organelle similar in structure to a lysosome; it
contains enzymes involved in hydrogen peroxide metabolism; it is abundant
in liver cells
Peyer's patches - aggregated lymph nodules that are most abundant
in the ileum; also called aggregated lymphatic follicles
phagocytosis - the process by which cells (phagocytes) ingest
particulate matter; especially ingestion and destruction of microbes, cell
debris, and other foreign matter
phalanx - the bone of a finger or toe; plural, phalanges
pharmacology - science that deals with the effects and uses of
drugs in the treatment of disease
pharynx - the throat; tube that starts at the internal nares and
runs partway down the neck, where it opens into the esophagus posteriorly
and the larynx anteriorly
phenotype - the observable expression of genotype; physical
characteristics of an organism, determined by the genetic makeup and
influenced by interactions between genes and internal and external
environmental factors
phenylketonuria (PKU) - a disorder characterized by elevated levels
of the amino acid phenylalanine in the blood
pheochromocytoma - a tumor of the chromaffin cells of the adrenal
medulla; results in hypersecretion of medullary hormones
phlebitis - inflammation of a vein, usually in the lower
extremities
phlebotomy - cutting of a vein to allow the escape of blood
phosphocreatine - a high-energy molecule in skeletal muscle fibers
(cells); phosphocreatine breaks down into creatine, phosphate, and energy;
the energy is used to generate ATP from ADP
phospholipid bilayer - the arrangement of phospholipid molecules in
two parallel rows, in which the hydrophilic heads face outward & the
hydrophobic tails face inward
phosphorylation - the addition of a phosphate group to a chemical
compound; the types include substrate-level, oxidative, and
photophosphorylation
physiology - science that deals with the functions of an organism
or its parts
pia mater - inner membrane (meninx), covering the brain and the
spinal cord
piezoelectric effect - a response of bone, mainly collagen, to
stress; very minute currents of electricity are produced and they are
believed to stimulate osteoblasts to make new bone cells
pilonidal - denoting a growth of hairs, resembling a tuft, inside a
cyst or a sinus
pineal gland - a cone-shaped gland located in the roof of the third
ventricle; also called the epiphysis cerebri
pinealocyte - secretory cell of the pineal gland; produces hormones
pinna - the projecting part of the external ear, composed of
elastic cartilage and covered by skin; shaped like the flared end of a
trumpet; also called the auricle
pinocytosis - the process by which cells ingest liquid
pituicyte - supporting cell of the posterior lobe of the pituitary
gland
pituitary dwarfism - condition caused by hyposecretion of human
growth hormone (hGH) during the growth years and characterized by
childlike physical traits in an adult
placenta - special structure through which exchange of materials
between fetal and maternal circulations occurs; also called the afterbirth
plantar flexion - bending the foot in the direction of the plantar
surface (sole)
plaque - any cholesterol-containing mass in the tunica media of
arteries; a mass of bacterial cells, dextran (polysaccharide), and other
debris that adheres to teeth
plasma - extracellular fluid found in blood vessels; blood minus
the formed elements
plasmapheresis - procedure in which blood is withdrawn from the
body, its components are selectively separated, undesireable components
(e.g., toxins, metabolic substances, and antibodies) causing disease are
removed, and the remainder is returned to the body
pleura - the serous membrane that covers the lungs and lines the
walls of the chest and diaphragm
plexus - a network of nerves, veins, or lymphatic vessels
pluripotent hematopoietic stem cell - immature stem cell in bone
marrow that gives rise to precursors of all the different mature blood
cells; also called a hemocytoblast
pneumonia - acute infection or inflammation of the alveoli of the
lungs
pneumotaxic area - portion of the respiratory center in the pons;
it sends inhibitory nerve impulses continually to the inspiratory area to
limit inspiration and to facilitate expiration
podiatry - diagnosis and treatment of foot disorders
poliomyelitis - a viral infection marked by fever, headache, stiff
neck and back, deep muscle pain and weakness, and loss of certain somatic
reflexes; a serious form, bulbar polio, results in destruction of motor
neurons in anterior horns of the spinal nerves, leading to paralysis
polycythemia - disorder characterized by hematocrit above normal
level of 55; hypertension, thrombosis, & hemorrhage occur
polyp - a tumor on a stem, especially on a mucous membrane
polysaccharides - carbohydrates in which 3 or more monosaccharides
are joined chemically
polyuria - an excessive production of urine
pons - portion of the brain stem that forms a bridge between the
medulla and the midbrain, anterior to the cerebellum
posterior - nearer to or at the back of the body; also called
dorsal
postganglionic neuron - the second visceral motor neuron in an
autonomic pathway, having its cell body and dendrites located in an
autonomic ganglion and its unmyelinated axon ending at cardiac muscle,
smooth muscle, or a gland
postpartum - after parturition; occurring after the delivery of a
baby
postsynaptic neuron - the nerve cell that is activated by release
of a neurotransmitter substance from another neuron and carries nerve
impulses away from the synapse
preeclampsia - syndrome during pregnancy characterized by sudden
hypertension, excessive amounts of protein in the urine, and generalized
edema; it might be related to an autoimmune or allergic reaction because
of the presence of a fetus
preganglionic neuron - the first visceral efferent neuron in an
autonomic pathway; its cell body and dendrites are in the brain or spinal
cord and its myelinated axon synapses with a postganglionic neuron in an
autonomic ganglion
premonitory - giving previous warning, as premonitory symptoms
prepuce - loose-fitting skin covering the glans of the penis or
clitoris; also called the foreskin
presbyopia - a loss of elasticity of the lens of the eye due to
advancing age, with resulting inability to focus clearly on near objects
presynaptic inhibition - inhibition of a nerve impulse before it
reaches a synapse; neurotransmitter released by the inhibitory neuron
depresses release of excitatory transmitter at the excitatory neuron
prevertebral ganglion - a cluster of cell bodies of postganglionic
sympathetic neurons, anterior to the spinal column and close to large
abdominal arteries; also called a collateral ganglion
primigravida - a woman pregnant for the first time
primordial - existing first; especially the primordial egg cells in
the ovary
proctology - the branch of medicine that treats the rectum and its
disorders
progeny - offspring or descendants
progesterone (PROG) - a female sex hormone produced by the ovaries;
it matures cells of the uterine endometrium and the mammary glands during
the luteal phase of a menstrual cycle
prognosis - a forecast of the probable results of a disorder; the
outlook for recovery
projection - the process by which the brain refers sensations to
their point of stimulation
prolactin (PRL) - a hormone secreted by the adenohypophysis
(anterior lobe) of the pituitary gland; initiates and maintains milk
secretion by the mammary glands
prolapse - a dropping or falling down of an organ, especially the
uterus or the rectum
proliferation - the rapid and repeated production of new parts,
especially cells
pronation - a movement of the forearm in which the palm of the hand
is turned posteriorly or inferiorly
properdin - a protein found in serum capable of destroying bacteria
and viruses
prophase - the first stage of mitosis during which the chromatid
pairs form and aggregate around the equatorial region of the cell
proprioception - the receipt of information from muscles, tendons,
and the labyrinth, enabling the brain to determine movements and to
position the body and its parts; also called kinesthesia
proprioceptor - a receptor located in muscles, tendons, or joints;
it provides information about body position and movements
prostaglandin (PG) - membrane-associated lipid composed of
20-carbon fatty acids, with 5 carbon atoms joined to form a cyclopentane
ring; it is synthesized in small quantities and, basically, mimics the
activities of hormones
prostate gland - the doughnut-shaped gland inferior to the male
urinary bladder; it surrounds the upper part of the urethra and it
secretes a slightly acid solution that contributes to sperm motility and
viability
prostatectomy - surgical removal of part of the prostate gland or
surgical removal of the entire prostate gland
prosthesis - artificial device to replace a missing body part
prothrombin - an inactive protein synthesized by the liver,
released into the blood, and converted to active thrombin in the process
of blood clotting
proto-oncogene - gene responsible for some aspect of normal growth
and development; it may be transformed into an oncogene, a gene capable of
causing cancer
protraction - movement of the mandible or shoulder girdle forward
on a plane parallel with the ground
proximal - nearer the attachment of an extremity to the trunk or a
structure; nearer to the point of origin
pruritis - itching
pseudopods - temporary, protruding projections of cytoplasm
psoriasis - chronic disease of the skin, characterized by reddish
plaques or papules covered with scales
psychosomatic - pertaining to the relation between mind and body;
commonly used to refer to those physiological disorders thought to be
caused, entirely or partly, by emotional disturbances
pterygopalatine ganglion - a cluster of cell bodies of
parasympathetic post-ganglionic neurons, ending at the lacrimal and nasal
glands
ptosis - drooping, as of the eyelid or the kidney
puberty - time of life during which the secondary sex
characteristics begin to appear and capability for sexual reproduction is
developed; usually between the ages of 10 and 17
puerperium - state immediately after childbirth, usually 4-6 weeks
pulmonary - concerning or affected by the lungs
pulmonary contusion - Pulmonary contusion usually
results from a severe blow to the chest that typically causes one or more
fractures. As mentioned previously, most pulmonary contusions are related
to the finding of a flail chest. Even if not readily apparent enough to be
life-threatening on initial evaluation, the resultant hemorrhage, edema,
and inflammation of the affected lung may later result in decreased
oxygenation and impaired ventilation. Treatment is usually individualized
based on the respiratory needs of the patient. If pulmonary contusion is
noted during the initial resuscitation, mechanical ventilation will
usually be necessary. During the subsequent evaluation, therapy directed
at the pulmonary contusion may prevent initiation of mechanical
ventilation with its attendant risks. Therapy includes limitation of
crystalloid fluid administration, aggressive pulmonary toilet, and
regional pain control.
punctate distribution - unequal distribution of cutaneous receptors
pyelitis - inflammation of the kidney pelvis and its calyces
pyemia - infection of the blood, with multiple abscesses, caused by
pus-forming organisms
pyloric sphincter - a thickened ring of smooth muscle through which
the pylorus of the stomach communicates with the duodenum; also called the
pyloric valve
pyogenesis - the formation of pus
pyorrhea - a discharge of flow of pus, especially in the alveoli
(sockets) and the tissues of the gums
pyramid - a pointed or cone-shaped structure; in the CNS, 1 of 2
triangular structures on the ventral medulla, comprising the largest motor
tracts from cerebral cortex to spinal cord; triangular renal medullary
structure comprising straight segments of renal tubules
pyramidal pathways - collections of motor nerve fibers arising in
the brain and passing down through the spinal cord to motor cells in the
anterior horns
pyrexia - a condition in which temperature is above normal
pyuria - presence of leucocytes and other components of pus in
urine
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Q -
quadrant - one of four parts
quadriplegia - paralysis of the two upper and two lower extremities
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R -
radiographic anatomy - diagnostic branch of anatomy that
includes the use of X-rays
rales - sounds sometimes heard in lungs; resemble bubbling or
rattling; due to presence of an abnormal amount or type of fluid or mucus
inside bronchi or alveoli or to bronchoconstriction, so that air cannot
enter or leave the lungs normally
rami communicantes - branches of a spinal nerve; singular, ramus
communicans
Raynaud's disease - vascular disease, primarily of females,
characterized by bilateral attacks of ischemia, usually of the fingers and
toes; the skin becomes pale and exhibits burning and pain as a result of
exposure to cold or to emotional stimuli
reactivity - the ability of an antigen to react specifically with
the antibody whose formation it induced
reciprocal innervation - the phenomenon by which action potentials
stimulate contraction of one muscle and simultaneously inhibit contraction
of antagonistic muscles
recruitment - the process of increasing the number of active motor
LETTERs; also called motor LETTER summation
rectum - the last 20 cm (7 in.) of the gastrointestinal tract, from
the sigmoid colon to the anus
recumbent - lying down
refraction - the bending of light as it passes from one medium to
another
refractory period - the time during which an excitable cell cannot
be made to respond to a stimulus that is usually adequate to evoke an
action potential
regeneration - the natural renewal of a structure
regimen - strictly regulated scheme of diet, exercise, or activity
designed to achieve certain ends
regurgitation - a return of solids or fluids from the stomach to
the mouth; blood flow backward through incompletely closed heart valves
relapse - return of a disease, weeks or months after its apparent
cessation
renal corpuscle - the glomerular (Bowman's) capsule and its
enclosed glomerulus
renal erythropoietic factor - an enzyme released by the kidneys and
liver in conditions of hypoxia; acts on a plasma protein to bring about
production of eyrthropoietin, a hormone that stimulates red blood cell
production
renin - an enzyme released by the kidney into plasma, where it
converts angiotensinogen into angiotensin I
renin-angiotensin pathway - mechanism for the control of
aldosterone secretion by angiotensin II; initiated by secretion of renin
from the kidney, in response to low blood pressure
reproduction - the formation of new cells for growth, replacement,
or repair, or the production of a new individual
residual volume - the volume of air still contained in the lungs
after maximal expiration; about 1,200 ml
resistance - resistance to blood flow as a result of viscosity,
blood vessel length, and blood vessel radius; hindrance to the flow of
electricity; hindrance to the flow of air as it moves through the
respiratory pasageways; the abililty to ward off disease
respiration - overall exchange of gases among the atmosphere, the
blood, and the body cells; it consists of pulmonary ventilation, external
respiration, & internal respiration
respirator - apparatus fitted to a mask over the nose and mouth, or
hooked directly to an endotracheal or tracheostomy tube; it is used to
assist or support ventilation or to provide nebulized medication to the
air passages under positive pressure
resuscitation - the act of bringing a person back to full
consciousness
rete testis - the network of ducts in the testis
retention - a failure to void urine due to obstruction, nervous
contraction of the urethra, or absence of sensation of the desire to
urinate
reticular activating syst. - the extensive network of branched
nerve cells running through the core of the brain stem; when these cells
are activated, a generalized alert or arousal behavior results
reticulocyte - an immature red blood cell
reticulum - a network
retina - inner coat of the eyeball, lying only in the posterior
portion of the eye and consisting of nervous tissue and a pigmented layer
comprising epithelial cells lying in contact with the choroid; also called
the nervous tunic
retinal - the pigment portion of the photopigment rhodopsin; also
called visual yellow
retraction - movement of a protracted part of the body backward on
a plane parallel to the ground, as in pulling the lower jaw back into line
with the upper jaw
retroflexion - positioning of the uterus in which it is tilted
posteriorly
retrograde degeneration - the changes occuring in the proximal
portion of a damaged axon only as far as the first neurofibral node (of
Ranvier); similar to the changes that occur during Wallerian degeneration
retroperitoneal - external to the peritoneum lining the abdominal
cavity
rheumatism - a painful state of the supporting structures of the
body, bones, ligaments, joints, tendons, or muscles
rhinology - the study of the nose and its disorders
rhinoplasty - the surgical procedure in which the structure of the
external nose is altered
rhodopsin - the photopigment in rods of the retina, consisting of a
protein scotopsin plus retinal; it is sensitive to low levels of
illumination; also called visual purple
ribonucleic acid (RNA) - a single-stranded nucleic acid;
nucleotides consist of a base (adenine, cytosine, guanine, or uracil),
ribose, and phosphate; the three types are messenger (m-RNA), transfer
(tRNA), and ribosomal (rRNA), all of which are necessary for protein
synthesis
ribosome - organelle in the cytoplasm of cells; composed of
ribosomal RNA and ribosomal proteins; nicknamed the protein factory
because of its role in protein synthesis
rickets - condition affecting children deficient in vitamin D;
characterized by soft and deformed bones, resulting from abnormal calcium
metabolism
rigidity - hypertonia characterized by increased muscle tone;
reflexes are not affected
roentgen - internation LETTER of radiation; a standard quantity of
X or gamma radiation
roentgenogram - image produced by X-rays on a photographic film
rotation - movement of a bone around its own axis, with no other
movement
rugae - large folds in the mucosa of an empty hollow organ, such as
the stomach or the vagina
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S -
saccule - the lower and smaller of two chambers in the
membranous labyrinth inside the vestibule of the inner ear; it contains a
receptor organ for static equilibrium
sacral promontory - the superior surface of the body of the first
sacral vertebra that projects anteriorly into the pelvic cavity; a line
from the sacral promontory to the superior border of the pubic symphysis
divides the abdominal and pelvic cavities
sagittal plane - vertical plane that divides the body or organs
into left and right portions; such a plane may be midsagittal (median),
with equal divisions, or parasagittal, with unequal divisions
saliva - a clear, alkaline, somewhat viscous secretion produced by
the three pairs of salivary glands; contains various salts, mucin,
lysozyme, and salivary amylase
salivary amylase - enzyme in saliva that initiates the chemical
breakdown of starch, mostly in the mouth
salpingitis - inflammation of the uterine (Fallopian) or auditory
(Eustachian) tube
sarcolemma - cell membrane of a muscle fiber (cell), especially, of
a skeletal muscle fiber
sarcoma - a connective tissue tumor, often highly malignant
sarcomere - the contractile LETTER in a striated muscle fiber
(cell) extending from one Z line to the next Z line
sarcoplasm - the cytoplasm of a muscle fiber (cell)
sarcoplasmic reticulum - a network of saccules and tubes
surrounding the myofibrils of a muscle fiber (cell), comparable to
endoplasmic reticulum; functions to reabsorb calcium ions during
relaxation and to release them to cause contraction
satiety - fullness or gratification, as of hunger or thirst
scala tympani - lower spiral-shaped channel of the bony cochlea,
filled with perilymph
scala vestibuli - upper spiral-shaped channel of the bony cochlea,
filled with perilymph
sciatica - inflammation & pain along the sciatic nerve; felt at the
back of the thigh, running down the inside of the leg
sclera - the white coat of fibrous tissue forming the outer
protective covering over the eyeball, except in the most anterior portion;
the posterior portion of the fibrous tunic
sclerosis - a hardening of tissues with loss of elasticity
scoliosis - abnormal lateral curvature compared with the normal
vertical line of the backbone
scotoma - area of depressed or lost vision within the visual field
scotopsin - the protein portion of the visual pigment rhodopsin,
found in rods of the retina
scrotum - a skin-covered pouch that contains the testes and their
accessory structures
sebaceous - secreting oil
sebum - the secretion of sebaceous (oil) glands
secretion - production and release from a gland cell of a fluid,
especially a functionally useful fluid as opposed to a waste product
sella turcica - depression on the superior surface of the sphenoid
bone; houses the pituitary gland
semen - a fluid discharged at ejaculation by a male; consists of a
mixture of spermatozoa and the secretions of the seminal vesicles, the
prostate gland, and the bulbourethral (Cowper's) glands; also called
seminal fluid
semilunar valve - valve guarding the entrance into the aorta or
pulmonary trunk from a ventricle of the heart
seminal vesicle - one of a pair of convoluted pouchlike structures,
lying posterior and inferior to the urinary bladder and anterior to the
rectum in the male; they secrete a component of semen into the ejaculatory
ducts
seminiferous tubule - tightly coiled duct, located in a lobule of
the testis, in which spermatozoa are produced
senescence - the process of growing old; the period of old age
senile macular degeneration - a disease in which blood vessels grow
over the macula lutea
senility - loss of mental or physical ability due to old age
sepsis - a morbid condition that results from the presence, in
blood or body tissues, of pathogenic bacteria & their products
septicemia - presence of toxins or disease-causing bacteria in
blood; also called blood poisoning
serosa - any serous membrane; the outermost layer of any organ,
formed by a serous membrane; the membrane that lines pleural, pericardial,
& peritoneal cavities
serous membrane - a membrane that lines a body cavity that does not
open to the exterior; also called the serosa
sesamoid bones - small bones usually found in tendons
sigmoid colon - the S-shaped portion of the large intestine,
beginning at the level of the left iliac crest, projecting inward toward
the midline, and terminating at the rectum, at about the level of the
third sacral vertebra
sigmoidoscopy - visualization of the anal canal, rectum, and colon
to: screen for colorectal cancer, collect samples for biopsy, remove
polyps, gather specimens for culture, and photograph the intestinal mucosa
simple pneumothorax - Usually diagnosed with a
chest radiograph, pneumothorax represents injury to the visceral pleura of
the lung resulting in air accumulation within the pleura space. This is
differentiated from a tension pneumothorax as the air space is not under
pressure and generally has no hemodynamic significance. Treatment consists
of tube thoracostomy.
sinoatrial (SA) node - a compact mass of cardiac muscle fibers
(cells) that are specialized for conduction & located in the right atrium
beneath the opening of the superior vena cava; also called the sinuatrial
node or pacemaker
sinus - hollow in a bone (paranasal sinus) or other tissue; a
channel for blood (vascular sinus); any cavity having a narrow opening
sinusitis - an inflammation of the mucous membrane of a paranasal
sinus
sinusoid - microscopic space or passage for blood in certain
organs, such as the liver or spleen
Snellen test - a test used to evaluate any problems or changes in
vision by measuring visual acuity
somatic nervous system - a portion of the peripheral nervous system
made up of the somatic efferent fibers that run between the central
nervous system and the skeletal muscles and skin
somatomedin - a small protein produced by the liver in response to
human growth hormone (hGH) stimulation; it mediates most of the effects of
hGH
somesthetic - pertaining to sensations & sensory structures of the
body
somite - block of mesodermal cells in a developing embryo; can be
distinguished into a myotome (forms most of the skeletal muscles), a
dermatome (forms connective tissues), and a sclerotome (forms the
vertebrae)
spasm - a sudden, involuntary contraction of large groups of
muscles
spastic - being characterized by an increase in muscle tone
(stiffness), accompanying increased tendon reflexes and abnormal reflexes
(Babinski sign)
spasticity - hypertonia, characterized by increased muscle tone,
increased tendon reflexes, and pathological reflexes (Babinski sign)
spermatic cord - supporting structure of the male reproductive
system, extending from the testis to the deep inguinal ring; it includes
the ductus (vas) deferens, arteries, veins, lymphatics, nerves, a
cremaster muscle, and connective tissue
spermatogenesis - formation and development of spermatozoa in the
seminiferous tubules of the testis
spermatozoon - a mature sperm cell
spermicide - any agent that kills spermatozoa
spermiogenesis - the maturation of spermatids into spermatozoa
sphincter - circular muscle constricting an orifice
sphygmomanometer - instrument for measuring arterial blood pressure
spina bifida - a congenital defect of the vertebral column in which
the halves of the neural arch of a vertebra fail to fuse in the midline
spinal cord - a mass of nerve tissue located in the vertebral canal
from which 31 pairs of spinal nerves originate
spinous process - sharp or thornlike process or projection; also
called a spine; the sharp ridge running diagonally across the posterior
surface of the scapula
spirometer - apparatus used to measure air capacity of the lungs
splanchnic - pertaining to the viscera
spleen - a large mass of lymphatic tissue between the fundus of the
stomach and the diaphragm; functions in phagocytosis, the production of
lymphocytes, and blood storage
sputum - substance ejected from the mouth, containing saliva and
mucus
squamous - scalelike
starvation - loss of energy stores in the form of glycogen, fats,
and proteins, due to inadequate intake of nutrients or inability to
digest, absorb, or metabolize ingested nutrients
stasis - a stagnation or halt of normal flow of fluids (as the
blood or urine) or of the intestinal mechanism
static equilibrium - the maintenance of posture in response to
changes in the orientation of the body, mainly the head, relative to the
ground
stell. reticuloendothel. cell - phagocytic cell that lines a
sinusoid of the liver; also called a Kupffer's cell
stenosis - an abnormal narrowing or constriction of a duct or
opening
stereocilia - groups of extremely long, nonmotile microvilli,
projecting from the epithelial cells lining the epididymis
stereognosis - an ability to recognize the size, shape, and texture
of an object by touch
sterile - free from any living micro-organisms; unable to conceive
or produce offspring
sterilization - an elimination of all living microorganisms;
rendering an individual incapable of reproduction; e.g., castration,
vasectomy, or hysterectomy
strabismus - a condition in which the visual axes of the two eyes
differ, so that they do not fix on the same object; condition of being
cross-eyed
stratum basalis - the outer layer of endometrium, next to the
myometrium, that is maintained during menstruation and gestation; it
produces a new functionalis following menstruation or parturition
stratum functionalis - the inner layer of the endometrium, adjacent
to the uterine cavity, that is shed during menstruation; forms the
maternal portion of the placenta during gestation
stricture - a local constriction of a tubular structure
stroma - the tissue that forms the ground substance, foundation, or
framework of an organ, as opposed to its functional parts
stupor - state of unresponsiveness from which a patient can be
aroused only briefly and by vigorous and repeated stimulation
subarachnoid space - space between the arachnoid and the pia mater;
it surrounds the brain and the spinal cord; cerebrospinal fluid circulates
through it
subcutaneous - underneath the skin; also called hypodermic
subdural space - a space between the dura mater and the arachnoid
of the brain and spinal cord; it contains a small amount of fluid
sublingual gland - one of the pair of salivary glands situated in
the floor of the mouth under the mucous membrane, to the side of the
lingual frenulum; its duct (Rivinus's) opens into the floor of the mouth
submandibular gland - salivary gland beneath the base of the tongue
under the mucous membrane in the posterior floor of the mouth (behind
sublingual glands); duct (Wharton's) situated to the side of the lingual
frenulum; also called the submaxillary gland
submucosa - layer of connective tissue located beneath a mucous
membrane, as in the gastrointestinal tract or the urinary bladder; the
submucosa connects the mucosa to the muscularis tunic
subserous fascia - layer of connective tissue internal to the deep
fascia, lying between deep fascia and the serous membrane lining the body
cavities
sudoriferous gland - an apocrine or exocrine gland in the dermis or
subcutaneous layer; produces perspiration; also called a sweat gland
sulcus - groove or depression between parts, especially between the
convolutions of the brain; plural, sulci
summation - algebraic addition of the excitatory and inhibitory
effects of all stimuli applied simultaneously to a nerve cell body
(spatial); increased strength of muscle contraction resulting when stimuli
occur in rapid succession (temporal)
superficial - located on or near the surface of the body
superior - toward the head of upper part of a structure; also
called cephalad or craniad
supination - movement of the forearm in which the palm of the hand
is turned anteriorly or superiorly
suppuration - pus formation & discharge
surfactant - a phospholipid substance produced by the lungs; it
decreases surface tension
susceptibility - a lack of resistance of a body to the deleterious
or other effects of agents such as pathogenic micro-organisms
suspensory ligament - fold of peritoneum extending laterally from
the surface of the ovary to the pelvic wall
sustentacular cell - a supporting cell of seminiferous tubules;
produces a hormone (inhibin) as well as secretions supplying nutrients to
spermatozoa; also called a Sertoli cell
sutural bone - small bone located within a suture between certain
cranial bones; also called Wormian bone
suture - an immovable fibrous joint in the skull where bone
surfaces are closely LETTERed
sympathetic division - autonomic nervous system subdivision;
preganglionic neuron cell bodies are in thoracic and upper lumbar segments
of the spinal cord; primarily concerned with processes involving energy
expenditure; also called the thoracolumbar division
sympathomimetic - producing effects mimicking those brought about
by the sympathetic division of the autonomic nervous system
symphysis - a line of union; a slightly movable cartilaginous
joint, e.g., the symphysis pubis between the anterior surfaces of the
coxal (hip) bones
symptom - a subjective change in body function not apparent to an
observer, such as fever or nausea, that indicates the presence of a
disease or disorder of the body
synapse - the junction between the processes of two adjacent
neurons; the place where the activity of one neuron affects the activity
of another; may be electrical or chemical
synapsis - the pairing of homologous chromosomes during prophase I
of meiosis
synaptic cleft - the narrow gap that separates the axon terminal of
one nerve cell from another nerve cell or muscle fiber (cell) and across
which a neurotransmitter diffuses to affect the postsynaptic cell
synarthrosis - an immovable joint
synchondrosis - a cartilaginous joint in which connecting material
is hyaline cartilage
syncope - a faint; sudden temporary loss of conciousness associated
with loss of postural tone and followed by a spontaneous recovery; most
commonly caused by cerebral ischemia
syndesmosis - a fibrous joint in which articulating bones are
LETTERed by dense fibrous tissue
syndrome - a group of signs and symptoms that occur together in a
pattern that is characteristic of a particular disease or abnormal
condition
syneresis - process of clot retraction
synergist - a muscle that assists the prime mover by reducing
undesired action or unnecessary movement
synergistic effect - a hormonal interaction in which the effects of
two or more hormones complement each other so that the target cell
responds to the sum of the hormones; an example is the combined actions of
estrogens, progesterone, prolactin, and oxytocin in lactation
synostosis - a joint in which the dense fibrous connective tissue
that LETTERes bones at a suture has been replaced by bone, resulting in a
complete fusion across the suture line
synovial cavity - the space between the articulating bones of a
synovial (diarthrotic) joint filled with synovial fluid; also called a
joint cavity
syphilis - a sexually transmitted disease caused by the bacterium
Treponema pallidum
systemic lupus erythematosus - autoimmune inflammatory disease that
may affect every tissue of the body; characterized by weakness, fever,
fatigability, joint pain or arthritis, reddish skin lesions,
lymphadenopathy, and malfunctions of many organ systems; also called SLE
systole - a part of the cardiac cycle; the phase of contraction of
the heart muscle, especially the ventricles
systolic blood pressure - force exerted by blood on the arterial
walls during ventricular contraction; highest pressure measured in the
large arteries, about 120 mm Hg under normal conditions for young, adult
males
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T -
tachycardia - a rapid heartbeat or pulse rate
tactile - pertaining to the sense of touch
taenia coli - one of the three flat bands of thickened,
longitudinal muscles running the length of the large intestine
tarsus - a collective term for the seven bones of the ankle
Tay-Sachs disease - inherited, progressive neuronal degeneration of
the central nervous system due to a deficient lysosomal enzyme; it causes
excessive accumulations of a lipid called ganglioside
tectorial membrane - gelatinous membrane projecting over, and in
contact with, the hair cells of the spiral organ (organ of Corti) in the
cochlear duct
telophase - final stage of mitosis, in which the daughter nuclei
become established
tendon - a white fibrous cord of dense, regularly arranged
connective tissue that attaches muscle to bone
tension pneumothorax - Injury to the visceral
pleura of the lung or other portions of the upper airway may result in a
rapid, one-way accumulation of air within the pleural space. Eventually,
intrapleural pressure increases and causes compression of the mediastinal
structures. The end result is depression of venous return to the heart,
resulting in significant hemodynamic instability. Hallmarks include
decreased breath sounds on the affected side, deviation of the trachea
away from the affected side, and marked hypotension. Diagnosis is
generally clinical, and not radiographic. Treatment consists of rapid
evacuation of the air within the pleural space. This may be done initially
with something as simple as a needle or intrevenous catheter. Tube
thoracostomy then follows. This situation is exacerbated by the presence
of positive pressure ventilation. More definitive treatment generally
depends on the nature of the injury.
tenosynovitis - inflammation of a tendon sheath and synovial
membrane at a joint
tentorium cerebelli - a transverse shelf of dura mater; forms a
partition between the occipital lobe of the cerebral hemisphere and the
cerebellum; covers the cerebellum
teratogen - agent or factor that causes physical defects in
developing embryos
terminal ganglion - cluster of postganglionic parasympathetic
neuronal cell bodies, either lying very close to the visceral effectors or
located within the walls of the visceral effectors supplied by those
postganglionic fibers
testis - a male gonad; it produces sperm and the hormones
testosterone and inhibin; also called a testicle; plural, testes
testosterone - male sex hormone (androgen) secreted by interstitial
endocrinocytes (cells of Leydig) of mature testes; controls growth and
development of male sex organs
tetanus - infectious disease caused by the toxin of Clostridium
tetani and characterized by tonic muscle spasms, exaggerated reflexes,
lockjaw, and arching of the back; a smooth, sustained contraction produced
by a series of very rapid stimuli to a muscle
tetany - a nervous condition caused by hypoparathyroidism &
characterized by intermittent or continuous tonic muscle contractions of
the extremities
tetralogy of Fallot - combination of congenital heart defects: 1)
constricted pulmonary semilunar valve, 2) interventricular septal opening,
3) emergence of aorta from both ventricles (instead of from left only),
and 4) enlarged right ventricle
thalamus - large, oval structure located above the midbrain and
consisting of two masses of gray matter covered by a thin layer of white
matter
thalassemia - group of hereditary hemolytic anemias
thallium imaging - diagnostic procedure used to evaluate: blood
flow through coronary arteries, cardiac disorders, & effectiveness of drug
therapy; thallium concentrates in healthy myocardial tissue
therapy - the treatment of a disease or disorder
thermoreceptor - any receptor that detects changes in temperature
thoracic cavity - superior component of the ventral body cavity; it
contains two pleural cavities, the mediastinum, and the pericardial cavity
thoracolumbar outflow - fibers of the sympathetic preganglionic
neurons; they have their cell bodies in the lateral gray columns of
thoracic and upper lumbar segments of the spinal cord
thorax - the chest; the upper part of the trunk between the neck
and the abdomen
thrombin - the active enzyme formed from prothrombin; acts to
convert fibrinogen to fibrin
thrombocyte - a fragment of cytoplasm; is enclosed in a cell
membrane and lacks a nucleus; found in the circulating blood; plays a role
in blood clotting; also called a platelet
thrombolytic agent - chemical injected into the blood to dissolve
clots and restore circulation through direct or indirect activation of
plasminogen; examples include tissue plasminogen activator (t-PA),
streptokinase, & urokinase
thrombophlebitis - a disorder in which inflammation of the wall of
a vein is followed by blood clot (thrombus) formation
thrombosis - formation of a clot in an unbroken blood vessel,
usually a vein
thymectomy - surgical removal of the thymus gland
thymus - a bilobed organ, located in the upper mediastinum
posterior to the sternum and between the lungs that plays an essential
role in the immune mechanism of the body
thyroglobulin (TGB) - a large glycoprotein molecule, secreted by
follicle cells of the thyroid gland, in which iodine and tyrosine are
combined to form thyroid hormones
thyroid cartilage - largest single cartilage of the larynx,
consisting of two fused plates that form its anterior wall; also called
the Adam's apple
thyroxine (T4) - a hormone secreted by the thyroid gland; it
regulates growth and development, organic metabolism, and the activity of
the nervous system
tinnitus - ringing, roaring, or clicking in the ears
tonometry - a test used to measure the intraocular pressure as a
screen for glaucoma
tonsil - a multiple aggregation of large lymphatic nodules,
embedded in mucous membrane
topical - applied to a surface, rather than ingested or injected
torpor - state of lethargy and sluggishness preceding stupor, which
precedes semicoma, which precedes coma
toxic - pertaining to poison; poisonous
trabecula - an irregular latticework of thin plate of spongy bone;
fibrous cord of connective tissue serving as supporting fiber by forming a
septum that extends into an organ from its wall or capsule; plural,
trabeculae
trabeculae carneae - ridges and folds in the myocardium of the
ventricles
trachea - a tubular air passageway, extending from the larynx to
the fifth thoracic vertebra; also called the windpipe
tracheostomy - creation of an opening into the trachea through the
neck (below the cricoid cartilage), with insertion of a tube to facilitate
passage of air or evacuation of secretions
trachoma - chronic infectious disease of the conjunctiva and cornea
of the eye, caused by Chlamydia trachomatis
transfusion - a transfer of whole blood, blood components, or bone
marrow, directly into the bloodstream
transient ischemic attack - an episode of temporary, focal,
nonconvulsive cerebral dysfunction, caused by interference with the blood
supply to the brain
transplantation - the replacement of injured or diseased tissues
with natural ones from another part or another individual
transverse colon - portion of the large intestine extending across
the abdomen from right colic (hepatic) flexure to left colic (splenic)
flexure
trauma - an injury, either a physical wound or a psychic disorder,
caused by an external agent or force, such as a physical blow or emotional
shock; the agent or force that causes the injury
tremor - rhythmic, involuntary, purposeless contraction of opposing
muscle groups
treppe - the gradual increase in the amount of contraction of a
muscle caused by rapid, repeated stimuli of the same strength
triad - a complex of three LETTERs in a muscle fiber (cell),
composed of a transverse tubule and the segments of sarcoplasmic reticulum
on both sides of it
tricuspid valve - the atrioventricular (AV) valve on the right side
of the heart
trigeminal neuralgia - pain in one or more of the branches of the
trigeminal (V) nerve; also called tic doloureux
triglyceride - a lipid compound formed from one molecule of
glycerol and three molecules of fatty acids; used for concentrated energy
storage; prime component of adipose (fat) tissue; also called a neutral
fat
trigone - triangular area at the base of the urinary bladder
triiodothyronine (T3) - a hormone produced by the thyroid gland; it
regulates growth and development, organic metabolism, and the activity of
the nervous system
trochlea - a pulley-like surface
trophoblast - the outer covering of cells of the blastocyst
tropic hormone - a hormone whose target is another endocrine gland
tubal ligation - a sterilization procedure in which the uterine
(Fallopian) tubes are tied and cut
tuberculosis - infection of the lungs and pleurae caused by
Mycobacterium tuberculosis
tumor - a growth of excess tissue due to an unusually rapid
division of cells
tunica albuginea - the dense layer of white fibrous tissue covering
a testis or deep to the surface of an ovary
tympanic antrum - air space in the posterior wall of the middle
ear; it leads into the mastoid air cells or sinus
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U -
ulcer - an open lesion of the skin or a mucous membrane of the
body with loss of substance and necrosis of the tissue
umbilical - pertaining to the umbilicus or navel
umbilicus - small scar on the abdomen that marks the former
attachment of the umbilical cord to the fetus; also called the navel
uremia - the accumulation of toxic levels of urea and other
nitrogenous waste products in the blood
ureter - one of two tubes that connect the kidney with the urinary
bladder
urethra - the duct from the urinary bladder to the exterior of the
body; conveys urine in females and urine and semen in males
urinary bladder - a hollow, muscular organ, situated in the pelvic
cavity posterior to the pubic symphysis
urobilinogenuria - the presence of urobilinogen in the urine
urogenital triangle - region of the pelvic floor below the
symphysis pubis, bounded by the symphysis pubis and ischial tuberosities,
and containing the external genitalia
urology - the specialized branch of medicine that deals with the
structure, function, and diseases of the male and female urinary systems,
as well as the male reproductive system
urticaria - a skin reaction to certain foods, drugs, or other
substances to which a person may be allergic; hives
uterine tube - a duct that transports ova from the ovary to the
uterus; also called the oviduct or Fallopian tube
uterosacral ligament - a fibrous band of tissue extending from the
cervix of the uterus laterally to attach to the sacrum
uterovesical pouch - a shallow pouch formed by reflection of
peritoneum from the anterior surface of the uterus, at the junction of the
cervix and the body, to the posterior surface of the urinary bladder
uterus - hollow, muscular organ in females; it is the site of
menstruation, implantation, fetal development, and labor; also called the
womb
utricle - larger of two divisions of the membranous labyrinth
located inside the vestibule of the inner ear; contains a receptor organ
for static equilibrium
uvea - the three structures that together make up the vascular
tunic of the eye
uvula - a soft, fleshy mass, especially the V-shaped pendant part,
hanging down from the soft palate
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V -
vacuole - membrane-bound organelle that, in animal cells,
frequently functions in temporary storage or transport of materials
vagina - a muscular, tubular organ that leads from the uterus to
the vestibule, situated between the urinary bladder and the rectum of the
female
valvular stenosis - narrowing of a heart valve, usually the
bicuspid (mitral) valve
varicocele - a twisted vein; especially, the accumulation of blood
in the veins of the spermatic cord
varicose - pertaining to an unnatural swelling, as in the case of a
varicose vein
vasa recta - extensions of the efferent arteriole of a
juxtaglomerular nephron that run alongside the loop of the nephron (Henle)
in the medullary region
vasa vasorum - blood vessels that supply nutrients to larger
arteries and veins
vascular - pertaining to or containing many blood vessels
vasectomy - a means of sterilization of males in which a portion of
each ductus (vas) deferens is removed
vasoconstriction - the decrease in size of the lumen of a blood
vessel, caused by contraction of smooth muscle in the wall of the vessel
vasodilation - an increase in the size of the lumen of a blood
vessel caused by relaxation of the smooth muscle in the wall of the vessel
vasomotion - intermittant contraction and relaxation of smooth
muscle of the metarterioles and the precapillary sphincters; it results in
intermittent blood flow
vasomotor center - a cluster of neurons in the medulla that
controls the diameter of blood vessels, especially arteries
vena cava - one of two large veins that open into the right atrium,
returning to the heart all of the deoxygenated blood from the systemic
circulation, except the coronary circulation
venesection - opening of a vein for withdrawal of blood
ventral - pertaining to the anterior or front side of the body;
opposite of dorsal
ventral ramus - the anterior branch of a spinal nerve, containing
sensory and motor fibers to the muscles and skin of the anterior surface
of the head, neck, trunk, and the extremities
ventricle - a cavity in the brain or an inferior chamber of the
heart
ventricular fibrillation - asynchronous ventricular contractions
that result in cardiovascular failure
venule - a small vein that collects blood from capillaries and
delivers it to a vein
vermiform appendix - the twisted, coiled tube attached to the cecum
vermilion - area of the mouth where the skin on the outside meets
the mucous membrane on the inside
vermis - a central constricted area of the cerebellum, separating
the cerebellar hemispheres
vertebral canal - the cavity within the vertebral column formed by
the vertebral foramina of all the vertebrae and containing the spinal
cord; also called the spinal canal
vertigo - a sensation of spinning or movement
vesicle - small bladder or sac, containing liquid
vestibular membrane - membrane that separates the cochlear duct
from the scala vestibuli
vestibule - a small space or cavity at the beginning of a canal,
especially the inner ear, larynx, mouth, nose, and vagina
villus - a projection of the intestinal mucosal cells, containing
connective tissue, blood vessels, and a lymphatic vessel; functions in
absorption of end products of digestion; plural, villi
viscera - the organs inside the ventral body cavity; singular,
viscus
visceral - pertaining to the organs or to the covering of an organ
visceroceptor - receptor that provides information about the body's
internal environment
viscosity - the state of being sticky or thick
vitiligo - patchy, white spots on the skin, due to partial or
complete loss of melanocytes
vitreous body - a soft, jellylike substance filling the vitreous
chambers of the eyeball, lying between the lens and the retina
vulva - collective designation for the external genitalia of the
female; also called the pudendum
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W -
Wallerian degeneration - degeneration of the portion of the axon
and the myelin sheath of a neuron, distal to the site of injury
wheal - elevated lesion of the skin
white ramus communicans - the portion of a preganglionic
sympathetic nerve fiber that branches away from the anterior ramus of a
spinal nerve to enter the nearest sympathetic trunk ganglion
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X -
xiphoid - sword-shaped; the inferior portion of the sternum
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Y -
NO ENTRIES
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Z -
zona fasciculata - middle zone of the adrenal cortex; consists
of cells arranged in long, straight cords; secretes glucocorticoid
hormones
zona glomerulosa - outer zone of the adrenal cortex, directly under
the connective tissue covering; consists of cells arranged in arched loops
or round balls; secretes mineralocorticoid hormones
zona pellucida - a gelatinous glycoprotein layer internal to the
corona radiata; surrounds a secondary oocyte
zona reticularis - inner zone of the adrenal cortex; consists of
cords of branching cells that secrete sex hormones, primarily androgens
zygote - a single cell resulting from union of a male and female
gamete; a fertilized ovum
zymogenic - one of the cells of a gastric gland that secretes the
principal gastric enzyme precursor, pepsinogen; also called a peptic cell
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