abdominal cavity
The part of the body
between the bottom of the ribs and the top of the thighs, containing
most of the digestive and urinary systems along with some reproductive
organs.
ABO
blood groups blood groups
The system by which human
blood is classified, based on proteins occurring on red blood cells; the
four classification groups are A, AB, B, and O.
abortion
Termination of a
pregnancy; can occur because of natural causes (called a miscarriage) or
be a medical intervention .
abscess
An accumulation of pus
in a body tissue, usually caused by a bacterial infection.
ACE
inhibitor
A drug typically used to
treat high blood pressure (Angiotensin-Converting
Enzyme inhibitor).
achilles
tendon tendon
The tendon at the back of the lower leg
that connects the calf muscle to the heel bone.
acid-base
balance balance
The mechanisms that the
body uses to keep its fluids close to neutral (neither basic nor acidic)
so that the body can function properly
acidosis
A condition marked by
abnormally high acid levels in the blood, associated with some forms of diabetes,
lung disease, and severe kidney disease.
acid
reflux
A disorder in which acid
in the stomach comes up into the esophagus,
because the valve separating the stomach and esophagus does not function
properly.
acne
A skin condition
characterized by inflamed, pus-filled
areas that occur on the skin's surface, most commonly occurring during
adolescence.
acquired
A word describing any
condition that is not present at birth, but develops some time during
life.
acquired immunodeficiency syndrome
Infection by the human
immunodeficiency virus (HIV), which causes a weakening of the immune
system .
acute
Describes a condition or
illness that begins suddenly and is usually short-lasting.
acute
respiratory disease
An urgent condition in
which oxygen levels in the blood are lower than normal and breathing is
difficult.
addiction
Dependence on a substance
(such as alcohol or other drugs) or an activity, to the point that
stopping is very difficult and causes severe physical and mental
reactions.
adenitis
Infection and inflammation
of a gland, especially a lymph node.
adipose
tissue tissue
Another term for fatty
tissue; it stores energy, insulates, and cushions the body.
adjuvant therapy
The use of drugs or radiation therapy in the
treatment of cancer along with surgery.
adrenal failure
A condition in which the
adrenal glands do not produce enough of the hormones
that control important functions such as blood pressure.
adrenal glands
Two small glands
located on top of the kidneys that secrete several important hormones into the blood.
adverse reaction
An unintended and unwanted
side effect of some sort of treatment, usually drug therapy.
aerobic exercise
Physical activity during
which the heart and lungs must work harder to meet the body's increased oxygen
demand.
affective disorder
A mental disorder
involving abnormal moods and emotions; affective disorders include manic-depressive
disorder.
afterbirth
The placenta
and membranes that are eliminated from the woman's uterus following the birth of a child.
afterpains
Normal contractions of the
uterus after childbirth that usually occur for the first few days after
delivery.
AIDS
See Acquired immunodeficiency
syndrome.
AIDS-related
complex complex
Symptoms including weight
loss, fever, and enlarged lymph nodes experienced by people who are
infected with HIV but do not yet have
AIDS.
air
embolism
The blockage of an artery by air
bubbles, which may have entered during surgery or after an injury.
airway obstruction
Blockage of the passage of
air through the windpipe to the lungs.
airways
The passageways that air
moves through while traveling in and out of the lungs during breathing.
albinism
A condition in which
people are born with insufficient amounts of the pigment melanin, which
is responsible for hair, skin, and eye color.
alcoholic cardiomyopathy
Heart damage and failure
caused by intake of too much alcohol.
alimentary canal
Another term for the
digestive tract.
alkalosis
Dangerously decreased
acidity of the blood, which can be caused by high altitudes, hyperventilation, and
excessive vomiting.
alkylating
agents
Substances used in cancer
treatment that interfere with the division of cells.
allergen
A substance that causes an
allergic reaction.
allergic rhinitis
Irritation of the nasal
passages and the whites of the eyes, causing sneezing, runny nose, and
sore eyes.
allergy
A negative reaction to a
substance that in most people causes no reaction.
alopecia
Baldness or loss of hair,
mainly on the head, either in defined patches or completely; the cause
is unknown.
ALS
See amyotrophic
lateral sclerosis.
altitude sickness
Headaches, dizziness, and
nausea usually experienced at heights above 8,000 ft because of reduced oxygen
in the air.
Alzheimer
disease disease
A condition that occurs
late in life and worsens with time in which brain cells degenerate; it
is accompanied by memory loss, physical decline, and confusion.
amenorrhea
Absence of menstrual
periods, occurring either after or before menstruation has begun.
amniocentesis
A procedure in which a
small amount of amniotic fluid is removed from the mother’s womb in
order to detect abnormalities of the fetus.
amniotic fluid
Clear fluid that surrounds
a fetus during pregnancy and cushions and protects it.
amyotrophic
lateral sclerosis
The most common of a group
of disorders known as motor neuron diseases, in which the nerves
in the brain that control the movement of muscles degenerate and muscle
function is gradually lost; commonly called Lou Gehrig's disease.
anabolic steroid
A drug similar to the male
hormone testosterone that builds muscles
and strengthens bones, but has adverse side effects.
anal
fissure
A long, open sore on the
skin of the anus.
anal
fistula
An abnormal tubelike
passage connecting the anus to the surface of the
surrounding skin .
analgesic
A drug that relieves pain,
such as aspirin or acetaminophen.
anal sphincter
A ring of muscle fibers at
the opening of the rectum, controlling the opening and
closing of the anus.
anaphylactic shock
A life-threatening
allergic reaction resulting in difficulty breathing and low blood
pressure.
anatomy
The structure of bodies;
commonly refers to the study of body structure.
androgen
A hormone (such as testosterone) that
causes development of male characteristics and sex organs.
anemia
A condition in which the
blood does not contain enough hemoglobin, the compound that carries oxygen
from the lungs to other parts of the body .
anencephaly
A fatal birth defect in
which the brain and spinal cord
have failed to develop, resulting in the absence of a portion of the
skull and brain.
anesthesia
A loss of sensation in a
certain part of the body or throughout the body.
anesthetic
A substance that
temporarily causes a person to be unable to feel pain, either in a
certain area or over the entire body.
aneurysm
An abnormal swelling of
the wall of an artery, caused by a weakening in the vessel wall.
angina
pectoris pectoris
Pain experienced in the
chest, arms, or jaw because of a lack of oxygen to the heart muscle.
angioma
A tumor made of blood vessels or lymph
vessels that is not cancerous.
angioplasty
The use of surgery to make
a damaged blood vessel function properly again; may involve widening or
reconstructing the blood vessel.
anorexia
nervosa
A dangerous eating
disorder mainly affecting young girls in which the sufferer has an
intense fear of looking fat, avoids food, and loses weight excessively.
antacid
A drug that neutralizes
stomach acids; used to treat indigestion, heartburn, and acid reflux.
antibiotic resistance
The development by
bacteria of the ability to live in the presence of a certain antibiotic,
making treatment difficult.
antibiotics
Bacteria-killing
substances that are used to fight infection.
antibody
A protein made by white blood cells that reacts
with a specific foreign protein as part of the immune response.
anticoagulants
Drugs used to stop
abnormal blood clotting, such as to prevent stroke.
antiemetics
Drugs used to treat nausea
and vomiting.
antihistamine
A drug that relieves an
allergic reaction by stopping the effects of histamine, the substance
responsible for the negative symptoms associated with the reaction.
antihypertensives
Drugs used to relieve the
symptoms and prevent the damage that can occur from high blood pressure.
antioxidants
Substances that protect
against cell damage by guarding the cell from oxygen free radicals.
antipsychotics
Drugs used to treat severe
mental disorders.
antiseptics
Chemicals applied to the
skin that prevent infection by killing bacteria and other harmful
organisms.
anus
The opening through which
feces are passed from the body.
aorta
The main artery in the
body, carrying oxygenated blood from the heart to other arteries in the
body.
aortic
stenosis
Narrowing of the opening
of the aortic valve in the heart,
which increases resistance to blood flow from the left ventricle to the
aorta; commonly a birth defect
or caused by scarring and calcium accumulation in the valve from rheumatic fever.
apgar
score
A system for evaluating
the health of a newborn baby; rated on a scale of 0-10.
aplasia
The complete or partial
failure of any organ or tissue to grow.
aplastic
anemia
A severely reduced number
of red blood cells, white blood cells, and platelets.
apnea
A possibly
life-threatening condition in which breathing stops, for either a short
or long period of time.
appendectomy
Surgical removal of the appendix to
treat appendicitis.
appendicitis
Inflammation of the appendix.
appendix
A short, tubelike
structure that branches off the large intestine;
does not have any known function.
ARC
See AIDS-related complex.
arteriosclerosis
A disorder causing
thickening and hardening of artery walls.
arteritis
Inflammation of the walls
of an artery that causes the passageway to become narrower;
can lead to tissue damage because oxygen
is not properly supplied.
artery
A large blood vessel that
carries blood from the heart to tissues and organs in the body.
arthritis
A disease of the joints
characterized by inflammation, pain, stiffness,
and redness.
arthroscopy
A procedure used to
examine the inside of a joint using a viewing tube (an endoscope).
artificial insemination
Injection of semen
into the cervix.
artificial respiration/ventilation/ventilation
The forcing of air (either
by mouth-to-mouth or mouth-to-nose means) into the lungs of a person who
has stopped breathing.
ascites
Excess fluid in the
abdominal cavity, which leads to swelling.
ascorbic
acid
The chemical term for vitamin
C.
aspermia
The failure either to
produce or to ejaculate sperm.
asphyxia
The medical term for
suffocation; can be caused by choking on an object, by lack of oxygen
in the air, or by chemicals such as carbon monoxide, which reduce the
amount of oxygen in the blood.
asthma
A disorder characterized
by inflamed airways and difficulty breathing.
astigmatism
A disorder in which the
front surface of the eye (the cornea) is not correctly spherical,
resulting in blurry vision.
atherectomy
A procedure performed to
remove plaque that is blocking an
artery.
atheroma
Fatty deposits on the
inner walls of blood vessels, which can cause narrowing and decrease
blood flow.
atherosclerosis
Narrowing of the lining of
the arteries due to the accumulation of fat and other
materials; leads to coronary
heart disease, stroke, and
other disorders.
athlete's
foot
An infection between the
toes caused by a fungus, which leads to sore, cracked,
and peeling skin.
atresia
A birth defect in which a normal
body opening or canal is absent; usually requires surgical repair soon
after birth.
atria
The two upper chambers of
the heart; the singular form is atrium.
atrial fibrillation
An irregular heartbeat in
which the upper chambers of the heart (the atria) beat inconsistently
and rapidly.
atrial
flutter
An irregular heartbeat in
which the upper chambers of the heart (the atria) beat rapidly but
consistently.
atrial septal defect
A hole located in the wall
between the two upper chambers of the heart.
atrophy
The shrinkage or near
disappearance of a tissue or organ.
attention-deficit
disorder
A disorder mainly present
in children and adolescents, characterized by learning and behavior
problems, inability to pay attention, and sometimes hyperactivity.
audiogram
A graph showing a person's
hearing ability, determined from a set of tests examining hearing acuity
of different sound frequencies.
aura
A "warning"
signal that comes before a migraine headache or an epileptic seizure,
which might include emotions or sensations of movement or discomfort.
auscultation
The act of listening to
sounds within the body, such as the heartbeat, with a stethoscope.
autism
A mental disorder
characterized by an inability to relate to other people and extreme
withdrawal.
autoimmune disease
A disorder in which the
body’s immune system attacks itself.
autonomic nervous system
The part of the nervous
system that controls automatic body functions, such as heart rate,
sweating, pupil dilation, and digestion; divided into the sympathetic nervous
system and the parasympathetic
nervous system.
autopsy
The examination of a body
following death, possibly to determine the cause of death or for
research.
autosomal dominant
A term describing a gene
on any chromosome other than the sex chromosomes that produces its
effect whenever it is present; can also describe the effect of the gene
itself.
autosomal recessive
A term used to describe a gene
on any chromosome other than the sex chromosomes that produces its
effect only when two copies of it are present; can also describe the
effect of the gene itself.
axilla
Medical term for the
armpit.
