Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «N»:
Nine-day measles: An acute
highly contagious viral disease with fever, runny nose,
cough, red eyes, and a spreading skin rash. the measles,
also known as rubeola, is a potentially disastrous
disease. It can be complicated by ear infections,
pneumonia, encephalitis (that can cause convulsio...
NINR: The National Institute of Nursing Research, one of the National Institutes of Health....
Ninth cranial nerve
Ninth cranial nerve: The ninth cranial nerve is the glossopharyngeal nerve. The 12 cranial nerves, the glossopharyngeal nerve included, emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column.
The glossopharyngeal nerve supplies the ton...
NIOSH: The National Institute for Occupational Safety and Health, a US Federal agency responsible for conducting research and making recommendations for the prevention of work-related disease and injury.
Despite its name (which would suggest that it is part of the National Institutes of Health (NI...
Nipah virus: A virus that infects pigs and people in whom it causes a sometimes fatal form of viral encephalitis (brain inflammation). Nipah is the name of the first village the virus struck near Kuala Lumpur in Malaysia. The Nipah virus is similar to Hendra virus that was discovered in Australia in...
Nipple: The pigmented projection on the surface of
breast. Ducts that conduct milk from the mammary glands to the
surface of the breast exit
through the nipple. The surrounding flat area of pigmentation is the
Nipple absence: Medically called athelia, this is a rare condition but it is common in certain conditions. Athelia tends to occurs on one side (unilaterally) in children with the Poland sequence and on both sides (bilaterally) in certain types of ectodermal dysplasia.
The Poland sequence (named f...
Nipple confusion: A problem that may beset a bottlefed baby in which it forgets how to nurse on mother's nipple. Breastfeeding requires far more vigorous mouth and tongue motions and greater muscle coordination than bottlefeeding. On bottle nipples or even pacifiers, a newborn can forget how to nur...
Nipple discharge: See: Breast discharge....
Nipple shield: A cap or dome, usually made today of plastic (formerly, rubber), placed over the nipple and areola during nursing to permit the flow of milk, provide a larger surface for the baby to latch onto, and protect the breast if it is sore. However, because a nipple shield may reduce the sti...
Nipple, supernumerary: An extra nipple.
Supernumerary nipples are usually smaller than normal and vestigial
(nonfunctional, without accompanying mammary glands). They tend to
occur on along a roughly curved line extending from near the armpit,
through the center of the normal breast, and down to...
Nirenberg: See: Nirenberg, Marshall W....
Nirenberg , Marshall W.
Nirenberg , Marshall W.: (b. 1927) American biochemist who shared the 1968 Nobel Prize in Physiology or Medicine for his work in deciphering the genetic code.
Marshall Warren Nirenberg was born in New York City. In 1941, Marshall developed rheumatic fever, and the Nirenberg family moved to Orlando, ...
Nit: Nits are lice eggs. They are hard to see and are often
confused with dandruff or hair spray droplets. Nits are found firmly
attached to the hair shaft. They are oval and usually yellow to
white. Nits take about a week to hatch. All nits must be removed to
prevent reinfestation with lice. Th...
Nitric oxide: A compound that is toxic but which, paradoxically, plays a number of important roles in the body, including the following:
It acts as a vasodilator (blood vessel relaxant).
It therefore controls blood flow to tissues.
It regulates the binding and release of oxygen to hemoglobin.