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Nebulization: Administration of medication to selected portions of the
respiratory tract by droplets suspended in air.
Necrosis:
Cell death due to infection or
injury.
Negative
feedback: The principle governing most control systems; a mechanism of
response in which a stimulus initiates actions that reverse or reduce the
stimulus.
Neonatal:
Pertaining to the first four weeks after birth.
Neoplasm:
A new growth that may be benign or malignant.
Nerve:
A cordlike bundle of nerve fibers (axons and/or dendrites) and its
associated connective tissue coursing together outside the central nervous
system.
Neural Tube Defect (NTD):
A birth defect caused by abnormal
development of the neural tube, the structure which gives rise to the
central nervous system. Neural tube defects include anencephaly and spina
bifida.
Neurologic: (or
neurological): Involving nerves or the nervous system (brain, spinal cord,
and all sensory and motor nerves).
Neuropathy:
Malfunction or disease pathology
of nerves. Peripheral neuropathy refers to a disease or degenerative state
of peripheral nerves resulting in pain, numbness, and sometimes muscle
weakness.
Neurotoxic:
Toxic or damaging to nervous
tissue (brain and peripheral nerves).
Neurotransmitter:
A chemical that is released from
a nerve cell, which transmits an impulse from that nerve cell to another
nerve cell, or to another organ (a muscle, for example). Neurotransmitters
are chemical messengers that transmit neurological information from one cell
to another.
Neutrophils:
Also called polymorphonuclear
leukocytes because they are white blood cells with a multi-lobed nucleus.
Neutrophils combat infection by internalizing and destroying disease causing
organisms such as bacteria.
NIH:
The National
Institutes of Health are U.S. health agencies, devoted to medical research.
Administered under the Department of Health and Human Services (HHS), the
NIH consists of more than 20 separate Institutes and Centers.
Nucleic
acids: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Long
thread-like molecules made up of large numbers of nucleotides. Nucleotides
are composed of a nitrogen containing base, a 5-carbon sugar, and one or
more phosphate groups. The sequence of bases in DNA or RNA represents the
genetic (hereditary) information of a living cell.
Nucleotides:
Molecules composed of a nitrogen
containing base, a 5-carbon sugar, and one or more phosphate groups. Long
strands of nucleotides form nucleic acids (see above). The sequence of bases
in DNA or RNA represents the genetic (hereditary) information of a living
cell.
Nucleus:
A
membrane-bound cellular organelle, which contains DNA organized into
chromosomes.
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