AskDefine | Define gonad

Dictionary Definition

gonad n : a gland in which gametes (sex cells) are produced [syn: sex gland]

User Contributed Dictionary

English

Noun

gonad (plural: gonads)
  1. A sex organ that produces gametes; specifically, a testicle or ovary.
  2. (slang, used only in plural gonads) The testicles.

Translations

sexual gland
slang, testicles

Extensive Definition

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 gonad term can refer to either male gonads (testicles) or female gonads (ovaries), the vernacular, or slang use of "gonads" (or "nads") usually only refers to the testicles.

Function

In addition to producing gametes, the gonads are a combined glands providing both exocrine and endocrine functions. The male and female gonads produce steroid sex hormones, identical to those producted by adrenal cortical cells. The major distinction is the source and relative amounts produced.

Testes

The male gonads, known as the testes or testicles, secrete a class of hormones called androgens, and produce spermatozoa. The predominant androgen in males is testosterone.

Regulation

The gonads are controlled hormonally by luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secreted by the anterior pituitary gland. The anterior pituitary gland's excretion of LH and FSH are, in turn, controlled by the hypothalamus' gonadotropin-releasing hormone.

Development

Gonads start developing as a common anlage, in the form of gonadal ridges, and only later are differentiated to male or female sex organs. The SRY gene, located on the Y chromosome and encoding the testis determining factor, decides the direction of this differentiation.
In 1943, Matthew Browne started a development of gonads in a part of the development of the urinary and reproductive organs.
gonad in Catalan: Gònada
gonad in Danish: Gonade
gonad in German: Gonade
gonad in Estonian: Sugunääre
gonad in Spanish: Gónada
gonad in French: Gonade
gonad in Ido: Gonado
gonad in Italian: Gonadi
gonad in Lithuanian: Lytinė liauka
gonad in Macedonian: Гонада
gonad in Dutch: Gonade
gonad in Polish: Gonada
gonad in Portuguese: Gónada
gonad in Russian: Гонада
gonad in Simple English: Gonad
gonad in Slovenian: Spolna žleza
gonad in Finnish: Sukupuolirauhaset
gonad in Swedish: Könskörtel
gonad in Thai: ต่อมบ่งเพศ
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