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epilepsy

(Encyclopedia)epilepsy, a chronic disorder of cerebral function characterized by periodic convulsive seizures. There are many conditions that have epileptic seizures. Sudden discharge of excess electrical activity,...

menstruation

(Encyclopedia)menstruation, periodic flow of blood and cells from the lining of the uterus in humans and most other primates, occurring about every 28 days in women. Menstruation commences at puberty (usually betwe...

muscle

(Encyclopedia)muscle, the contractile tissue that effects the movement of and within the body. Muscle tissue in the higher animals is classified as striated, smooth, or cardiac, according to its structure and funct...

Tay-Sachs disease

(Encyclopedia)Tay-Sachs disease tāˈ-săksˈ [key], rare hereditary disease caused by a genetic mutation that leaves the body unable to produce an enzyme necessary for fat metabolism in nerve cells, producing cent...

pigmentation

(Encyclopedia)pigmentation, name for the coloring matter found in certain plant and animal cells and for the color produced thereby. Pigmentation occurs in nearly all living organisms. Almost all plants synthesize ...

chlorophyll

(Encyclopedia)CE5 chlorophyll klôrˈəfĭlˌ [key], green pigment that gives most plants their color and enables them to carry on the process of photosynthesis. Chemically, chlorophyll has several similar forms...

fever

(Encyclopedia)fever, elevation of body temperature above the normal level, which in humans is about 98℉ (37℃) when measured orally. Fever is considered to be a symptom of a disorder rather than a disease in its...

frozen foods

(Encyclopedia)frozen foods, products of the food preservation process of freezing. This process has been employed by people in the Arctic from prehistoric times. Eskimos throw fresh-caught fish on the ice to freeze...

melanin

(Encyclopedia)melanin mĕlˈənĭn [key], water-insoluble polymer of various compounds derived from the amino acid tyrosine. It is one of two pigments found in human skin and hair and adds brown to skin color; the ...

lupus

(Encyclopedia)lupus lo͞oˈpəs [key], noninfectious chronic disease in which antibodies in an individual's immune system attack the body's own substances. In lupus, known medically as lupus erythematosus, antibodi...