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hair

(Encyclopedia)CE5 A. Cross section of a hair shaft B. General structure of a hair hair, slender threadlike outgrowth from the skin of mammals. In some animals hair grows in dense profusion and is called fur or ...

hypersensitivity

(Encyclopedia)hypersensitivity, heightened response in a body tissue to an antigen or foreign substance. The body normally responds to an antigen by producing specific antibodies against it. The antibodies impart i...

cysteine

(Encyclopedia)CE5 CE5 cysteine sĭsˈtēn [key], organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer participates in the biosynthesis of mammalian protein...

estrogen

(Encyclopedia)CE5 estrogen ĕsˈtrəjən [key], any one of a group of hormones synthesized by the reproductive organs and adrenal glands in females and, in lesser quantities, in males. The estrogens cause the th...

radiation sickness

(Encyclopedia)radiation sickness, harmful effect produced on body tissues by exposure to radioactive substances. The biological action of radiation is not fully understood, but it is believed that a disturbance in ...

nicotine

(Encyclopedia)nicotine, C10H14N2, poisonous, pale yellow, oily liquid alkaloid with a pungent odor and an acrid taste. It turns brown on exposure to air. Nicotine, a naturally occurring constituent of tobacco, is t...

wings

(Encyclopedia)CE5 A. Structure of a bird wing B. Structure of a bat wing wings, flight organs of the bird, the bat, and the insect. Birds' wings are pectoral appendages that are basically the same in skeletal...

steroids

(Encyclopedia)CE5 Two examples of steroids steroids, class of lipids having a particular molecular ring structure called the cyclopentanoperhydro-phenanthrene ring system. Steroids differ from one another in th...

bromine

(Encyclopedia)bromine brōˈmēn, –mĭn [key] [Gr.,=stench], volatile, liquid chemical element; symbol Br; at. no. 35; at. wt. 79.904; m.p. –7.2℃; b.p. 58.78℃; sp. gr. of liquid 3.12 at 20℃; density of va...

Wilder, Thornton Niven

(Encyclopedia)Wilder, Thornton Niven, 1897–1975, American playwright and novelist, b. Madison, Wis., grad. Yale (B.A., 1920), Princeton (M.A., 1925). He received most of his early education in China, where his fa...