Medical terms - Letter N (page 8) | MedicalVocabulary.org

Nicotiana tabacum

A South American herb whose leaves contain 2-8% nicotine and serve as the source of smoking and smokeless tobacco and the basis of huge health problems. Nicotiana tabacum belongs to the nightshade family, which also…
Nicotine

Nicotine: An alkaloid (a nitrogen-containing chemical) made by the tobacco plant or produced synthetically. In the plant kingdom, nicotine is not restricted to tobacco but is widespread. The tobacco plant, Nicotiana…
Nicotinic acid

Deficiency of nicotinic acid (also known as niacin), one of the B-complex vitamins, causes pellagra. Pellagra was known as the 'disease of the four D's' -- dermatitis, diarrhea, dementia and death. The disease is…
Nictitate

To wink. Nictitating spasm is spasm of the eyelid with continuous winking. 'Nictitate' and the older verb 'nictate' both come from the Latin word for winking, 'nictare.'
Nictitating spasm

Spasm of the eyelid with continuous winking. To nictitiate is to wink. 'Nictitate' and the older verb 'nictate' both come from the Latin word for winking, 'nictare.'
NICU

Newborn, or Neonatal, Intensive Care Unit, an intensive care unit designed for premature and ill newborn babies. Less often, NICU may refer to a Neurologic Intensive Care Unit
NIDA

Stands for the National Institute on Drug Abuse, one of the National Institutes of Health in the U.S., whose mission is to 'lead the nation in bringing the power of science to bear on drug abuse and addiction through…
NIDCD

Stands for National Institute on Deafness and Other Communication Disorders, one of the US National Institutes of Health (the NIH). The mission of the National Institute on Deafness and Other Communication Disorders is…
NIDCR (National Institute of Dental Research)

Al Research: One of the National Institutes of Health (NIH) in the U.S., the NIDCR is for dental and other craniofacial diseases. NIDCR's mission is, in formal terms, to 'provide leadership for a national research…
NIDDK (Nat'l Institute of Diabetes and Kidney)

And Kidney Diseases): One of the National Institutes of Health in the U.S., the NIDDK has a multisystem name and a comparably broad mission, namely, to 'conduct and support basic and applied research and provide…
Nidus

The Latin word for 'nest', nidus is used in medicine to refer to any structure that resembles a nest in appearance or function. Just as a nest is a repository for the eggs of birds, insects and other animals, a nidus is…
NIEHS

Stands for National Institute of Environmental Health Sciences, one of the National Institutes of Health in the U.S., whose mission is to 'reduce the burden of human illness and dysfunction from environmental causes by…
Niemann-Pick disease

A biochemical disorder affecting a lipid (fat) called sphingomyelin, resulting usually in progressive enlargement of the liver and spleen (hepatosplenomegaly), 'swollen glands' (lymphadenopathy), anemia and mental and…
Niemann-Pick disease type A

The classical infantile form of the disease. See: Niemann-Pick disease
Niemann-Pick disease type C

Abbreviated NPC. A type of Niemann-Pick disease inherited in an autosomal recessive manner, resulting in lipid storage in the brain and body. At the cellular level, the disorder is characterized by the accumulation of…
Night blindness

Impaired vision in dim light and in the dark, due to impaired function of specific vision cells (namely, the rods) in the retina. The ability of our eyes to quickly view objects as they shift from light to dark areas…
Night sweats

Night sweats: Severe hot flashes which occur at night and result in a drenching sweat. Night sweats can have many different causes including medications, infections, and cancers.
NIGMS

Stands for the National Institute of General Medical Sciences, one of the National Institutes of Health in the U.S., whose mission is to 'support basic biomedical research that is not targeted to specific diseases or…
NIH

A genetic disease named for the city of Nijmegen (in The Netherlands) with increased chromosome breakage, immunodeficiency and an increased risk of malignancy. Children with the syndrome appear abnormal with stunted…
Nijmegen breakage syndrome

A genetic disease named for the city of Nijmegen (in The Netherlands) with increased chromosome breakage, immunodeficiency and an increased risk of malignancy. Children with the syndrome appear abnormal with stunted…
Nil disease

A form of kidney disease preferably called minimal change disease. See: Minimal change disease
NIMH

Stands for the National Institute of Mental Health, one of the National Institutes of Health in the U.S., whose mission is to 'provide national leadership dedicated to understanding, treating, and preventing mental…
NINDS

Stands for the National Institute of Neurological Disorders and Stroke, one of the National Institutes of Health in the U.S., whose mission is to 'support and conduct research and research training on the normal…
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…
NINR

The National Institute of Nursing Research, one of the National Institutes of Health
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…
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…
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…
Nipple

The pigmented projection on the surface of the 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 areola
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…
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…
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…
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…
Nirenberg

See: 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…
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…
Nitric oxide

>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. >It thereby controls the supply of oxygen to mitochondria…
Nitrogen

Element number 7, a colorless, odorless, tasteless gas that is biologically important. Nitrogen is a constituent of protein and nucleic acids and is present in all living cells. Nitrogen does not support respiration and…
Nitrogen narcosis

A condition similar to intoxication with alcohol with euphoria, loss of balance and manual dexterity, disorientation and impaired reasoning that occurs in divers below 100 feet (30 meters) who breath compressed air…
Nitrogen, liquid

See: Liquid nitrogen
Nitrogenous base

A molecule that contains nitrogen and has the chemical properties of a base. The nitrogenous bases in DNA are adenine (A), guanine (G), thymine (T), and cytosine (C). The nitrogenous bases in RNA are the same with one…
Nitrosoureas

A group of cancer drugs called alkylating agents because they act by the process of alkylation to inhibit DNA repair. The nitrosoureas can cross the blood-brain barrier and are used to treat brain tumors. The…
Nitrous oxide (laughing gas)

A gas that can cause general anesthesia. Nitrous oxide is sometimes given in the company of other anesthetic agents but it is not used today as the only anesthetic agent because the concentration of nitrous oxide needed…
NK cell

See Natural killer cell
NLD

Necrobiosis lipoidica diabeticorum
NLM (National Library of Medicine)

The world's largest medical library, the U.S. National Library of Medicine (NLM) is part of the National Institutes of Health (NIH). The NLM has as its mission to collect, organize, and make available biomedical science…
NMR

Nuclear Magnetic Resonance. An imaging technique that does not use radiation.
No show

Term used in the US for a patient who missed an appointment. (In the UK, a patient who failed an appointment 'did not attend.' This is abbreviated DNA, not to be confused with the genetic material.
Nocardia infection

Also called nocardiosis, infection with bacteria called Nocardia which tend to strike the lungs, brain and skin, particularly in people with an impaired immune system. The majority (about 80%) of cases of nocardiosis…