| Hair
follicle |
a
tiny opening in the skin from which a hair grows |
| Halitosis |
the
clinical term for bad breath; commonly caused by poor oral
hygiene or eating certain foods; if persistent it can be a
sign of illness |
| Hallucination |
a
perception that occurs when there is actually nothing there
to cause it (such as hearing voices when there are none) |
| Hammer
toe |
an
abnormality in the tendons of the toe that causes the toe
to be flexed at all times |
| Hamstring
muscle |
a
muscle located at the back of the thigh that bends the leg
at the knee and moves the leg backward |
| Hardening
of the arteries |
the
common name for arteriosclerosis |
| Hashimoto's
disease |
a
disease in which the body's immune system attacks cells of
the thyroid gland, resulting in a decrease in thyroid hormones |
| Hay
fever |
the
common name for allergic rhinitis |
| HDL |
see
High-density lipoprotein |
| Heart
attack |
see
Myocardial infarction |
| Heart
block |
a
disorder of the heart caused by a blockage of the nerve impulses
to the heart that regulate heartbeat; may lead to dizziness,
fainting, or stroke |
| Heartburn |
a
burning sensation experienced in the center of the chest up
to the throat; may be caused by overeating, eating spicy food,
or drinking alcohol; recurrent heartburn may be caused by
acid reflux |
| Heart
disease |
see
Coronary heart disease |
| Heart
failure |
the
inability of the heart to pump blood effectively |
| Heart-lung
machine |
a
machine that takes over the functions of the heart and lungs
during certain types of surgery |
| Heart
rate |
the
rate at which the heart pumps blood, measured in the number
of heartbeats per minute |
| Heart
valve |
the
structure at each exit of the four chambers of the heart that
allows blood to exit but not to flow back in |
| Heat
exhaustion |
fatigue,
dizziness, and nausea experienced because of overexposure
to heat; if not treated it can result in heat stroke |
| Heat
stroke |
a
life-threatening condition resulting from extreme overexposure
to heat, which disrupts the body's system of regulating temperature
|
| Heel
spur |
an
abnormal, often painful outgrowth of bone on the back of the
heel |
| Heimlich
maneuver |
a
first-aid technique for choking; dislodges an object that
is blocking a person's airway |
| Helper
T cells |
white
blood cells, responsible for regulating other cells in the
body's immune system, that are the main targets of the AIDS
virus; also called CD4 cells |
| Hemangioma |
a
purple-red mark on the skin, caused by an excess of blood
vessels |
| Hemarthrosis |
bleeding
into and swelling of a joint |
| Hematemesis |
vomiting
of blood |
| Hematocrit |
the
percentage of total blood volume that consists of red blood
cells, which is determined by laboratory testing; can be an
indicator of disease or injury |
| Hematoma |
an
accumulation of blood from a broken blood vessel |
| Hematuria |
blood
in the urine, which can be caused by urinary tract disorders
(such as cysts, tumor, or stones) or by an infection |
| Hemochromatosis |
a
genetic disorder in which too much iron is absorbed from food |
| Hemodialysis |
a
method used to treat kidney failure, in which blood is passed
through a machine that purifies it and returns it to the body |
| Hemoglobin |
the
pigment in red blood cells that is responsible for carrying
oxygen; hemoglobin bound to oxygen gives blood its red color |
| Hemoglobinuria |
hemoglobin
in the urine |
| Hemolysis |
the
breakdown of red blood cells in the spleen, which is normal
but can cause jaundice and anemia when the red blood cells
are broken down too quickly |
| Hemophilia |
an
inherited disorder in which a person's blood lacks a certain
protein important in forming blood clots, leading to excessive
bleeding |
| Hemorrhage |
the
medical term for bleeding |
| Hemorrhoid |
a
bulging vein either at the opening of the anus or just inside
the anus, often caused by childbirth or straining during bowel
movements |
| Hemospermia |
blood
in the semen |
| Hemostasis |
the
stopping of bleeding by the body's mechanisms |
| Hemothorax |
an
accumulation of blood between the chest wall and the lungs |
| Hepatectomy |
surgical
removal of all or part of the liver |
| Hepatic |
a
term used to describe something that is related to the liver |
| Hepatitis |
inflammation
of the liver, which may be caused by a viral infection, poisons,
or the use of alcohol or other drugs |
| Hepatitis
A |
a
form of hepatitis caused by the hepatitis A virus, usually
transmitted by contact with contaminated food or water |
| Hepatitis
B |
a
form of hepatitis (generally more serious than hepatitis A)
caused by the hepatitis B virus, which is transmitted through
sexual contact or contact with infected blood or body fluids |
| Hepatitis
C |
a
form of hepatitis caused by the hepatitis C virus, which is
transmitted through sexual contact or contact with infected
blood or body fluids |
| Hepatitis
D |
a
form of hepatitis that only causes symptoms when the individual
is already infected with hepatitis B |
| Hepatoma |
a
cancerous tumor of the liver |
| Hepatomegaly |
enlargement
of the liver |
| Hereditary |
describes
a genetic trait that is passed from parents to children |
| Hereditary
spherocytosis |
a
genetic disorder in which red blood cells are smaller, rounder,
and more fragile than normal, causing hemolytic anemia |
| Hermaphroditism |
a
rare condition in which an individual is born with both male
and female reproductive organs |
| Hernia |
the
bulging of an organ or tissue through a weakened area in the
muscle wall |
| Herniated
disk |
see
Disk prolapse |
| Herpes
encephalitis |
brain
inflammation caused by a herpes simplex virus that has spread
from another part of the body |
| Herpes
simplex |
infection
by the herpes simplex virus, which causes blisterlike sores
on the face, lips, mouth, or genitals; in rare cases, can
also affect the eyes, fingers, or brain |
| Herpes
zoster |
see
Shingles |
| Heterosexuality |
being
sexually attracted to members of the opposite sex |
| Hiatal
hernia |
a
type of hernia in which the stomach bulges up into the chest
cavity through an opening in the diaphragm |
| Hiccup |
involuntary
sudden contraction of the diaphragm along with the closing
of the vocal cords, producing a "hiccup" sound |
| High-density
lipoprotein |
a
type of protein found in the blood that removes cholesterol
from tissues, protecting against heart disease |
| Hirschsprung's
disease |
a
condition that is present at birth in which nerve cells do
not develop in parts of the intestine, causing the intestine
to narrow and block the passage of feces |
| Hirsutism |
excessive
hair or hair growth in unusual places, especially in women |
| Histamine |
a
chemical in some cells of the body that is released during
allergic reactions, causing inflammation; also causes production
of acid in the stomach and narrowing of the airways |
| H1
(histamine) blocker |
a
drug that blocks the action of histamine; used to treat inflammation |
| H2
(histamine) blocker |
a
drug used in the treatment of peptic ulcers that blocks histamine
from causing acid production in the stomach |
| Histoplasmosis |
a
respiratory disease acquired by inhaling the spores of a fungus
found in soil, especially where there are bird or bat droppings |
| HIV |
see
Human immunodeficiency virus |
| Hives |
the
common term for urticaria, an itchy, inflamed rash that results
from an allergic reaction |
| Hodgkin's
disease |
a
cancer of lymphoid tissue (found in lymph nodes and the spleen)
that causes the lymph nodes to enlarge and function improperly;
may cause illness, fever, loss of appetite, and weight loss |
| Homeostasis |
the
body's coordinated maintenance of the stable, internal environment
by regulating blood pressure, blood sugar, body temperature,
etc |
| Homocystinuria |
a
genetic disorder in which an enzyme deficiency causes a substance
called homocystine to build up in the blood, leading to mental
handicap and skeletal abnormalities |
| Homosexuality |
being
sexually attracted to members of the same sex |
| Hookworm |
infestation
by a small, round, blood-sucking parasite; commonly causes
a rash on the foot, but can also cause cough, pneumonia, and
anemia |
| Hormonal
implant |
surgical
insertion of a small object just under the skin that slowly
releases a synthetic hormone for purposes such as birth control
|
| Hormone |
a
chemical produced by a gland or tissue that is released into
the bloodstream; controls body functions such as growth and
sexual development |
| Hormone
replacement therapy |
the
use of natural or artificial hormones to treat hormone deficiencies |
| Hospice |
a
hospital or an area of a hospital dedicated to treating people
who are dying, often of a specific cause |
| Hot
flash |
a
sudden, temporary feeling of heat and sometimes sweating;
usually occurs as a result of low estrogen levels in women
because of menopause or after a hysterectomy |
| HTLV |
see
Human T-cell lymphotrophic virus |
| Human
immunodeficiency virus |
a
retrovirus that attacks helper T cells of the immune system
and causes acquired immunodeficiency syndrome (AIDS); transmitted
through sexual intercourse or contact with infected blood
|
| Human
T-cell lymphotrophic virus |
a
virus similar to HIV that affects the same helper T cells,
but usually accompanies adult T-cell leukemia or T-cell lymphomas |
| Hydramnios |
an
excess of amniotic fluid in the uterus during pregnancy |
| Hydrocele |
a
painless swelling of the scrotum, caused by a collection of
fluid around the testicle; commonly occurs in middle aged
men |
| Hydrocephalus |
excess
cerebrospinal fluid within the brain; commonly referred to
as "water on the brain" |
| Hydrocortisone |
a
corticosteroid drug that is used to treat inflammation and
allergies |
| Hygiene |
the
practice, maintenance, and study of health; commonly refers
to cleanliness |
| Hymen |
a
thin fold of membrane partly closing the opening of the vagina;
usually torn during first sexual intercourse or insertion
of a tampon |
| Hyperactivity |
a
type of behavior characterized by excessive physical activity,
sometimes associated with neurological or psychological causes |
| Hyperalimentation |
a
method of providing nutrients by the use of a tube or intravenously
to a person who cannot eat food or needs nutrients because
of an illness |
| Hyperbilirubinemia |
a
condition in which there is too much bilirubin, a substance
produced when red blood cells are broken down; can lead to
jaundice |
| Hypercalcemia |
a
condition marked by abnormally high levels of calcium in the
blood; can lead to disturbance of cell function in the nerves
and muscles and, if not treated, can be fatal |
| Hypercholesterolemia |
an
abnormally high level of cholesterol in the blood, which can
be the result of an inherited disorder or a diet that is high
in fat |
| Hyperglycemia |
a
condition characterized by abnormally high levels of glucose
in the blood, usually as a result of untreated or improperly
controlled diabetes mellitus |
| Hyperlipidemia |
a
general term for a group of disorders in which lipid levels
in the blood are abnormally high, including hypercholesterolemia
|
| Hyperparathyroidism |
overactivity
of the parathyroid glands, which increases calcium levels
in the blood (called hypercalcemia) and decreases calcium
in bones (causing osteoporosis) |
| Hyperplasia |
the
enlargement of an organ or tissue |
| Hypersensitivity |
an
excessive response of the body's immune system to a foreign
protein |
| Hypertension |
abnormally
high blood pressure, even when at rest |
| Hyperthermia |
an
abnormally high body temperature |
| Hyperthyroidism |
overactivity
of the thyroid gland, causing nervousness, weight loss, fatigue,
and diarrhea |
| Hypertrophy |
increase
in the size of an organ due to an increase in the size of
its cells |
| Hyperventilation |
abnormally
rapid breathing |
| Hypochondriasis |
an
abnormal condition in which a person is overly concerned with
health and believes that he or she is suffering from a major
illness despite medical opinion to the contrary |
| Hypodermic
needle |
a
thin, hollow needle attached to a syringe; used to inject
a medication under the skin, into a vein, or into a muscle |
| Hypoglycemia |
abnormally
low levels of glucose in the blood |
| Hypoplasia |
failure
of a tissue or organ to develop normally |
| Hypotension |
the
medical term for abnormally low blood pressure, which results
in reduced blood flow to the brain, causing dizziness and
fainting |
| Hypothermia |
an
abnormally low body temperature |
| Hypothyroidism |
underactivity
of the thyroid gland, causing tiredness, cramps, a slowed
heart rate, and possibly weight gain |
| Hypoventilation |
a
slower-than-normal breathing rate |
| Hypoxemia |
a
reduced level of oxygen in the blood |
| Hypoxia |
a
reduced level of oxygen in tissues |
| Hysterectomy |
surgical
removal of the uterus |
| Hysteria |
a
term used to describe symptoms that are caused by mental stress
and occur in someone who does not have a mental disorder |
| Hysterosalpingography |
an
X-ray examination performed to examine the inside of the uterus
and fallopian tubes, in order to investigate and possibly
treat infertility |
| Hysteroscopy |
a
method used to examine the inside of the uterus and the cervix
using a viewing instrument |
