gonad


gonad
gonadal, gonadial /goh nay"dee euhl/, gonadic /goh nad"ik/, adj.
/goh"nad, gon"ad/, n. Anat.
a sex gland in which gametes are produced; an ovary or testis.
[1875-80; < NL gonad- (s. of gonas), equiv. to gon- GON- + -ad- -AD1]

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      in zoology, primary reproductive gland that produces reproductive cells (gametes). In males the gonads are called testes; the gonads in females are called ovaries. (see ovary; testis).

      The gonads in some lower invertebrate groups (e.g., hydrozoans) are temporary organs; in higher forms they are permanent. In some invertebrates, such as oligochaete worms and leeches, both male and female gonads exist in a single organism. Sponges do not have discrete gonads; instead, reproductive cells are formed by aggregations of amoebocytes in the body wall. In echinoderms (e.g., starfish), the gonads are usually suspended from the radiating arms directly into the sea.

      The usually paired gonads of vertebrates produce both gametes and hormones necessary for reproduction. Some, such as both male and female adult cyclostomes, have only one gonad. Most female birds, a few female teleost and elasmobranch fishes, some male lizards and female crocodiles, and the female platypus and a few female bats also have only one gonad.

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Universalium. 2010.

Look at other dictionaries:

  • Gonad — Gon ad, n.; pl. {Gonads}. [Gr. ? that which generates.] (Anat.) One of the masses of generative tissue primitively alike in both sexes, but giving rise to either an ovary or a testis; a generative gland; a germ gland. Wiedersheim. [1913 Webster] …   The Collaborative International Dictionary of English

  • gonad — gonad. См. гонада. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • gonad — 1880, from Mod.L. gonas (pl. gonades), coined from Gk. gone, gonos seed, act of generation, race, family, from gignesthai be born, related to genos race, birth, descent (see GENUS (Cf. genus)). Related: gonads …   Etymology dictionary

  • gonad — ► NOUN ▪ a bodily organ that produces gametes; a testis or ovary. DERIVATIVES gonadal adjective. ORIGIN Latin gonades, plural of gonas, from Greek gon generation, seed …   English terms dictionary

  • gonad — [gō′nad΄] n. [< ModL gonas (pl. gonades) < Gr gonē, a seed, generation < IE * gon < base * ĝen , to produce > GENUS] an organ or gland in animals that produces reproductive cells; esp., an ovary or testis gonadal adj …   English World dictionary

  • Gonad — A reproductive gland (ovary or testis) that produces germ cells (gametes). In embryonic life, the gonad in males and females is initially identical. This gonad is said to be indifferent before it differentiates into a definitive testis or ovary.… …   Medical dictionary

  • Gonad — The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells. For example, spermatozoon and egg cells are gametes. Although medically the… …   Wikipedia

  • gonad — UK [ˈɡəʊnæd] / US [ˈɡoʊˌnæd] noun [countable] Word forms gonad : singular gonad plural gonads medical a sex organ that makes cells used in producing babies. In men this sex organ is called a testicle, and in women it is called an ovary …   English dictionary

  • gonad — noun Etymology: New Latin gonad , gonas, from Greek gonos Date: 1880 a reproductive gland (as an ovary or testis) that produces gametes • gonadal adjective …   New Collegiate Dictionary

  • gonad(o)- — [L. gonas, gen. gonadis gonad, from Gr. gonos procreation] a combining form denoting relationship to the gonads …   Medical dictionary


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