| 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 |
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 |
The
tendon at the back of the lower leg that connects the calf
muscle to the heel bone |
| Acid-base
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 |
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 |
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 |
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 |
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 |
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 |
