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nares - plural, Latin naris = nostril.
naris - Latin = nostril, plural - nares.
nasal - adjective, Latin nasus = nose; hence, pertaining to the nose.
Nasalis(L. nasus, nose). - Pertaining to the nose.
natal - adjective, Latin natus = born; hence, relating to birth.
Nausea - An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various
stomach infections.
navicular - adjective, Latin navicula = a little ship (cf. naval); hence, the tarsal bone which is concave posteriorly, resembling a boat.
Necrosis - The sum of the morphological changes indicative of cell death and caused by the progressive degradative action of enzymes, it may affect groups of cells or part of a structure or an organ.
Needle Biopsy - Needle biopsy is a procedure using a needle to take a sample of tissue or fluid. The procedure is also called fine needle aspiration.
negative feedback - a sensing mechanism detects a change in conditions beyond specific limits. A control center evaluates the change and activates the change and activates a second mechanism to correct the
condition. The variant condition is canceled, or negated, so that conditions are returned to normal.
neo- - Greek prefix - neos = new.
neonatal - adjective, Greek neos = new, and Latin natos = born; hence, new-born.
neopallium - Greek neos = new, and Latin pallium = cloak; hence, the cerebral cortex which developed more recently than the archipallium or olfactory cortex.
Neoplasia - New and abnormal growth of tissue (neoplasm), which may be benign or cancerous, that serves no purpose.
Neoplasm - Also called tumor. Any new and abnormal growth; specifically a new growth of tissue in which the growth is uncontrolled and progressive. Malignant neoplasms are distinguished from benign in that the
former show a greater degree of anaplasia and have the properties of invasion and metastasis.
Nephron - The nephron is the functional unit of the kidney that is responsible for the actual purification and filtration of the blood. About one million nephrons are in the cortex of each kidney, and each one
consists of a renal corpuscle and a renal tubule which carry out the functions of the nephron.
Filtering units that number over a million in the kidneys.
nerve - Latin nervus = tendon; later reserved for a peripheral bundle of fibres which conduct impulses from or to the central nervous system.
nervous system - consists of two parts: the central nervous system and the peripheral nervous system.
nervous tissue - tissue that consists of two kinds of nerve cells, neurons and neuroglia.
neural - adjective, Greek neuron = nerve.
Neurilemma - The plasma membrane surrounding a Schwann cell of a myelinated nerve fiber and separating layers of myelin.
Neuroblastoma - A childhood tumor that arises in the adrenal gland or in tissue in the nervous system that is related to the adrenal gland.
Neuroendocrine - Descriptive of cells that release a hormone into the circulating blood in response to a neural stimulus. Such cells may comprise a peripheral endocrine gland (e.g., the insulin-secreting beta
cells of the islets of Langerhans in the pancreas and the adrenaline-secreting chromaffin cells of the adrenal medulla); others are neurons in the brain (e.g., the neurons of the supraoptic nucleus that release antidiuretic hormone
from their axon terminals in the posterior lobe of the hypophysis).
Neurofibromatosis - A disorder inherited as an autosomal dominant and characterized especially by brown spots on the skin, neurofibromas of peripheral nerves, and deformities of subcutaneous tissue and bone.
Neuroglia - Supporting tissue intermingled with the essential elements of nervous tissue especially in the brain, spinal cord, and ganglia.
Cells that support and protect neurons.
neurohypophysis - or posterior lobe of hypophysis - Greek hypo = down, and physis = growth; hence, the posterior part of the hypophysis evaginated downwards from the diencephalon, and its stalk.
neurolemma - Greek neuron = nerve, and lemma = peel or rind; hence, the covering layer of a nerve.
Neuron - A grayish or reddish granular cell with specialized processes that is the fundamental functional unit of the nervous tissue.
A cell that transmits nerve impulses. Refers to the nerve cell body, with its axon and dendrites; adjective - neuronal.
neurophysiology - the study of how the nervous system functions.
Neutron - A neutron is a subatomic particle found in the nucleus of every atom except that of simple hydrogen. The particle derives its name from the fact that it has no electrical charge; it is neutral.
The neutral charge in the nucleus of an atom.
nigra - Latin niger = black, dark.
NK (Natural Killer) Cells - Natural killer cells are large lymphocytes. They are the first line of defense against viruses and other invaders because they do not need to wait for an antibody response to
identify foreign cells and invaders.
node - Latin nodus = knot.
nodule - diminutive of Latin nodus = knot, hence, a little knot.
norma - Latin = pattern or rule, or aspect; adjective, normal - according to rule.
notch - an indentation in the margin of a structure. Etymology uncertain.
Notochord - An axial mesodermal tissue found in embryonic stages of all chordates and protochordates, often regressing as maturity is approached. Typically a rod shaped mass of vacuolated cells. It lies
immediately below the nerve cord and may provide mechanical strength to the embryo.
notochord - Greek notos = back, and chorde = cord; hence, the primitive axial skeleton around which the vertebrae develop, parts persisting in the nuclei pulposi.
nucha - French nuque = nape or back of the neck; adjective - nuchal.
Nuchae(F. nuque, back of the neck). Muscles associated with
the back of the neck.
nuclear division - divides the genetic material in the nucleus.
Nuclear Medicine - Nuclear medicine is a medical specialty that uses very small amounts of radioactive materials or radiopharmaceuticals to diagnose and and treat disease. It is safe, painless, and cost-
effective.
nuclei - clusters of cell bodies in the central nervous system.
nucleus - the part of the cell that contains DNA, the hereditary information of the cell. Latin = kernel or nut; may refer to the vital centre of a cell body, or to a cluster of neuron cells in the central nervous system; adjective - nuclear.
nystagmus - Greek = drowsiness, to nod, hence, involuntary, rapid, rhythmic eye movements.
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