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narcolepsy
A disorder that causes
excessive sleepiness during the day and frequent and uncontrollable
episodes of falling asleep.
narcosis
A drug (or other
chemical)-induced drowsiness or stupor.
narcotic
An addictive substance
that blunts the senses; can cause confusion, stupor, coma, and death with increased dosages.
narcotic analgesics
A type of painkiller that
blocks the transmission of pain signals in the brain; often cause
tolerance (the need for higher amounts of the drug to produce the same
effect) and drug dependence.
nasal
septum
The section of the nose
that divides the left and right nostrils; made of cartilage
and bone and covered by a mucous
membrane.
nasogastric
tube
A thin, plastic tube that
is inserted through the nose, down the esophagus, and into the stomach;
used to drain, wash, or take samples from the stomach, or to feed very
sick patients who cannot eat.
nasopharynx
The passageway connecting
the back of the nose to the top of the throat.
natural childbirth
A technique of giving
birth that stresses relaxation techniques so that the use of
pain-relieving drugs can be minimized; also called prepared childbirth.
natural
methods of family planning
Methods of planning a
family that focus on a woman's time of ovulation,
either so that pregnancy can be avoided or conception is likely.
nausea
Feeling the need to vomit.
nebulizer
An instrument that
provides a drug in its misted form through a face mask; used for severe
asthma attacks and for children who have asthma
but cannot use an inhaler.
necrosis
The medical term for the
death of tissue cells.
needle
aspiration
The use of a thin, hollow
needle and syringe to remove body fluid for examination.
needle
biopsy
The use of a hollow,
wide-diameter needle to remove a sample of tissue for examination.
neonate
A term used to describe a
newborn infant from birth to 1 month of age.
neoplasm
Another term for a tumor.
nephrectomy
The surgical removal of
one or both kidneys.
nephritis
Inflammation of one or
both kidneys because of an infection,
an abnormal immune system
response, or a disorder of metabolism.
nephroblastoma
A fast-growing cancer of the kidneys that occurs most
commonly in children under 4 years of age.
nephrolithotomy
Surgical removal of a kidney stone.
nephrons
The tiny filtering units
of the kidney.
nephrosclerosis
The replacement of normal
kidney structures with scar tissue.
nephrostomy
The surgical placement of
a tube into the kidney to drain
urine.
nephrotic syndrome
Symptoms that result from
damage to the filtering units of the kidney.
nerve
A bundle of fibers that
transmit electrical messages between the brain and areas of the body;
these messages convey sensory or motor function information.
nerve
block
The dulling of sensation
in an area of the body by injecting a painkiller into or around a nerve
leading to that section of the body.
nerve
cell
The basic unit of the
nervous system; transmits chemical messages throughout the body.
nerve compression
Pressure on a nerve, which
can cause nerve damage and muscle weakness.
neuralgia
Pain along the course of a
nerve
caused by irritation or damage to the nerve.
neural
tube
The tube located along the
back of an embryo that later
develops into the spinal cord
and brain.
neural tube defects
Problems in the
development of the spinal cord and brain in an embryo, such as the failure of the
spine to enclose the spinal cord (spina
bifida) and the failure of the brain to develop (anencephaly).
neuritis
Inflammation of a nerve, often
characterized by pain, numbness, or tingling; also used to describe
nerve damage and disease from causes other than inflammation.
neuroblastoma
A cancerous childhood
tumor located in the adrenal
glands or the sympathetic
nervous system.
neurofibrillary tangles
Abnormal spiral filaments
on nerve cells in the brain; characteristic of Alzheimer disease.
neurofibromatosis
A condition in which
connective tissue tumors occur on nerves in the skin.
neuroleptic
An antipsychotic drug.
neuroma
A noncancerous tumor occurring in nerve
tissue.
neuron
Another term for a nerve cell.
neuropathy
Disease, inflammation, or
damage to the nerves connecting the brain and spinal cord to the rest of the
body.
neurosis
Relatively mild emotional
disorders (such as mild depression
and phobias).
neurotoxins
Chemicals that attack and
damage nerve cells.
neurotransmitters
Chemicals that transfer
messages from one nerve cell to another or from a nerve cell to a muscle
cell.
neutrophil
A type of white blood cell.
nevus
A marking on the skin; can
be present at birth (birthmark) or develop later (such as a mole).
newborn respiratory
distress syndrome
A disorder in which
premature babies lack surfactant,
a substance that stops the lungs from collapsing.
niacin
A vitamin important in
many chemical processes in the body; also known as vitamin B3.
night
terrors
A form of nightmare
causing abrupt awakening in terror; occurs mostly in children.
nitrates
A group of drugs that
widen blood vessels; used to treat insufficient blood supply to the
heart (angina pectoris) and reduced
pumping efficiency of the heart (heart
failure).
nocturia
Urination or a
sleep-disturbing need to urinate during the night.
nocturnal emission
Ejaculation of semen
during sleep, which is normal in adolescent males; commonly called a wet
dream.
node
A small, rounded tissue
mass.
nodule
A small lump of tissue
that is usually abnormal; can form under the skin or protrude.
nondisjunction
An error that occurs
during the division of sex chromosomes, causing either too much or too
little genetic information to be placed in an egg or sperm when it is
formed.
non-Hodgkin's lymphoma
Any cancer in lymphoid
tissue (found mostly in the spleen and lymph glands) that is not Hodgkin's disease.
non-insulin-dependent diabetes
A type of diabetes mellitus that
occurs mainly in those over 40 who are overweight; it is usually treated
with diet changes and drugs that increase production of insulin by the pancreas (also known as type II
diabetes mellitus).
noninvasive
A term that is used to
describe medical procedures that do not enter or penetrate the body;
also refers to noncancerous tumors
that do not spread to other sections of the body.
nonnarcotic analgesic
A drug that relieves pain
by blocking the production of chemicals that stimulate pain-sensing nerves.
nonsteroidal
anti-inflammatory drugs
A group of drugs that
relieve pain and reduce inflammation.
norepinephrine
A hormone
that regulates blood pressure
by causing blood vessels to narrow and the heart to beat faster when
blood pressure drops.
norwalk
virus
A virus that causes acute gastroenteritis.
nosocomial infection
An infection acquired in a
hospital.
NSAID
See nonsteroidal
anti-inflammatory drug.
nucleic
acids
Substances found in every
living organism that provide the instructions for development; includes DNA and RNA.
nucleotide
bases
Molecules that form
nucleic acids.
nucleus
The center or most
important point of an object.
numbness
The lack of sensation in a
part of the body because of interruption of nerve
impulses.
nurse-midwife
A registered nurse who
specializes in the care of a mother and child during pregnancy, labor,
and delivery.
nutrient
Any substance that the
body can use to maintain its health.
nystagmus
Persistent, rapid,
involuntary movement of the eyes.
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