Medical Dictionary Definitions A-Z List

Medical Dictionary Definitions A - Z - «N»:

NeurotransmitterNeurotransmitter: A chemical that is released from a nerve
cell which thereby transmits an impulse from a nerve cell to another
nerve, muscle, organ, or other tissue. A neurotransmitter is a
messenger of neurologic information from one cell to another....

Neutral foot typeNeutral foot type: The most common type of foot. A runner with a neutral type of foot lands on the
heel and rolls forward during the gait cycle until the impact is distributed evenly across the forefoot....

Neutral postureNeutral posture: The posture when the joints are not bent and the spine is aligned and not twisted. Working in neutral postures is preferable to working while twisting the back or bending the wrists....

NeutropeniaNeutropenia: Not enough neutrophils, neutrophils being a type of white blood cell (specifically a form of granulocyte) filled with neutrally-staining granules, tiny sacs of enzymes that help the cell to kill and digest microorganisms it has engulfed by phagocytosis. The mature neutrophil has a segme...

Neutropenia, severe congenital (SCN)Neutropenia, severe congenital (SCN): Children born with this condition lack neutrophils (a type of white blood cell that is important in fighting infection). These children suffer frequent infections from bacteria which in the past led to death in three-quarters of cases before 3 years of age. This...

NeutrophilNeutrophil: A type of white blood cell, specifically a form of granulocyte, filled with neutrally-staining granules, tiny sacs of enzymes that help the cell to kill and digest microorganisms it has engulfed by phagocytosis. The mature neutrophil has a segmented nucleus (it is called a seg or poly) w...

NeutrophiliaNeutrophilia: More than the normal number of
neutrophils, a type of white blood cell (specifically a form of granulocyte) filled with neutrally-staining granules, tiny sacs of enzymes that help the cell to kill and digest microorganisms it has engulfed by phagocytosis. The mature neutrophil has a s...

NevusNevus: 1. Any birthmark.
2. A benign pigmented spot on the skin such as a mole (a cluster of melanocytes and supportive tissue that appears as a tan, brown, or flesh-colored spot on the skin).
3. A benign blood vessel tumor on the skin such as a vascular nevus, a local collection of capillaries of t...

New England Journal of MedicineNew England Journal of Medicine: Despite its regional name, The New England Journal of Medicine (NEJM) is far from provincial. It is an eminent weekly national and international general medical journal, devoted to no single specialty, but to all of medicine. The Journal is published by the Massachus...

New variant Creutzfeldt-Jakob diseaseNew variant Creutzfeldt-Jakob disease: Abbreviated nvCJD. A human disease thought due to the same infectious agent as bovine spongiform encephalopathy (BSE), or mad cow disease. Both the human and bovine disorders are invariably fatal brain diseases with unusually long incubation periods measured in...

New, fear of theNew, fear of the: An irrational fear of anything new, of innovation, of new situations, places, or things. Also called neophobia.
In animal behavior, neophobia refers to the tendency of an animal to avoid or retreat from an unfamiliar object or situation.
All phobias are unreasonable sorts of fea...

Newborn hearing screenNewborn hearing screen: Testing of the newborn baby's ability to hear. Newborn screening of hearing is done with automated auditory brainstem response tests or, less often, with what are called otoacoustic emission or conventional auditory brainstem response tests. The aim is to detect those babies ...