Columbia Encyclopedia

Search results

500 results found

Eccles, Sir John Carew

(Encyclopedia)Eccles, Sir John Carew kârˈē, ĕkˈəlz [key], 1903–97, Australian neurophysiologist. He was educated at the Univ. of Melbourne and at Magdalene College, Oxford. He was director (1937–44) of th...

aldosterone

(Encyclopedia)aldosterone ălˌdōstĭrōnˈ [key], steroid secreted by the cortex of the adrenal gland. It is the most potent hormone regulating the body's electrolyte balance. Aldosterone acts directly on the kid...

colchicine

(Encyclopedia)colchicine kŏlˈchəsēnˌ [key], alkaloid extracted from plants of the genus Colchicum and especially from the corms of the autumn crocus, Colchicum autumnale (see meadow saffron). The metabolic eff...

endoderm

(Encyclopedia)endoderm ĕnˈdədûrmˌ [key], in biology, inner layer of tissue formed in the gastrula stage of the developing embryo. At the end of the blastula stage, cells of the embryo are arranged in the form ...

intoxication

(Encyclopedia)intoxication, condition of body tissue affected by a poisonous substance. Poisonous materials, or toxins, are to be found in heavy metals such as lead and mercury, in drugs, in chemicals such as alcoh...

injection

(Encyclopedia)injection, introduction of a fluid into the body, usually by means of a needle and syringe. The material injected may be a test substance (as in determining allergic sensitivity or immunity to a disea...

hearing aid

(Encyclopedia)hearing aid, device used in some forms of deafness to amplify sound before it reaches the auditory organs. Modern hearing aids are electronic. They contain a tiny receiver and a transistor amplifier, ...

notochord

(Encyclopedia)notochord nōˈtəkôrdˌ [key], in biology, supporting rod running most of the length of animals of the phylum Chordata and present at varying times in the life cycle. Composed of large cells packed ...

Ohsumi, Yoshinori

(Encyclopedia)Ohsumi, Yoshinori, 1945–, Japanese biologist, Ph.D. Univ. of Tokyo, 1974. He was a researcher at the Univ. of Tokyo from 1977 to 1996, when he joined the National Institute for Basic Biology in Japa...

Leeuwenhoek, Antony van

(Encyclopedia)Leeuwenhoek, Antony van änˈtōnē vän lāˈvənho͞okˌ [key], 1632–1723, Dutch student of natural history and maker of microscopes, b. Delft. His use of lenses in examining cloth as a draper's a...