| 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 |
