|
-
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
Return
to top
-
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
Return
to top
-
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
Return
to top
-
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
Return
to top
-
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
Return
to top
-
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
Return
to top
-
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
Return
to top
-
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
Return
to top
-
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 |