| gonad | <biology> A sex organ, such as an ovary or a testicle, which produces the gametes in most multicellular animals. (09 Oct 1997) |
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| gonad dose | The exposure dose to the male or female gonad, usually from incidental secondary radiation in diagnostic or therapeutic irradiation, or from whole-body irradiation. Synonym: gonadal dose. (05 Mar 2000) |
| gonad nucleus | <cell biology> The smaller nucleus in ciliate protozoans, fully active in inheritance and passed after meiosis to conjugating pairs. Gives rise to the macronucleus or macronuclei. Genes in the micronucleus are not actively transcribed. (18 Nov 1997) |
| gonadal | <anatomy> Pertaining to a gonad. (18 Nov 1997) |
| gonadal agenesis | Congenital absence of essentially all gonadal tissue; the external genitalia and genital ducts are female, but if interstitial cells of Leydig are present, the external genitalia are commonly ambiguous and the genital ducts are female. See: gonadal dysgenesis. Compare: Klinefelter's syndrome, Turner's syndrome. Synonym: gonadal agenesis. (05 Mar 2000) |
| gonadal aplasia | Congenital absence of essentially all gonadal tissue; the external genitalia and genital ducts are female, but if interstitial cells of Leydig are present, the external genitalia are commonly ambiguous and the genital ducts are female. See: gonadal dysgenesis. Compare: Klinefelter's syndrome, Turner's syndrome. Synonym: gonadal agenesis. (05 Mar 2000) |
| gonadal cords | Columns of germinal and follicle cells penetrating centripetally into the embryonic ovarian or testicular cortex. (05 Mar 2000) |
| gonadal disorders | Disease of the ovaries and testes of any aetiology. (12 Dec 1998) |
| gonadal dose | The exposure dose to the male or female gonad, usually from incidental secondary radiation in diagnostic or therapeutic irradiation, or from whole-body irradiation. Synonym: gonadal dose. (05 Mar 2000) |
| gonadal dysgenesis | <embryology, genetics> A rare genetic disorder in women that is characterised by the absence of an X chromosome. This disorder inhibits normal sexual development and causes infertility. Features include webbing of the neck, short stature, retarded development of secondary sex characteristics, absence of menses, coarctation of the aorta, low hairline, eye abnormalities (drooping eyelids) and skeletal deformities. Treatment include oestrogen supplementation at puberty. Growth hormone replacement may be necessary in some cases. Cardiac surgery may be necessary to correct coarctation of the aorta. Incidence: 1 in 3,000 births. (10 Oct 1997) |
| gonadal dysgenesis, 46,xy | A syndrome characterised by "streak gonads" in a phenotypic female with a 46,xy karyotype. It is due to a mutation which inhibits the function of the y-borne determinant that would normally cause the indifferent embryonic gonad to differentiate into a testis. The streak gonad is incapable of ovulation or oestrogen secretion. The syndrome is sometimes called "pure gonadal dysgenesis," but this designation may also refer to the presence of streak gonads with a 46,xx karyotype. (12 Dec 1998) |
| gonadal dysgenesis, mixed | A syndrome of gonadal dysgenesis in which there is a testis on one side and a "streak gonad" on the other. The phenotype is generally male, but may be female since the individual is a mosaic. Various karyotypes have been identified, including 45,xo/47,xyy; 45,xo/46,xy; and 45,xo/46,xyo. (12 Dec 1998) |
| gonadal hormones | Hormones having oestrogenic (female sex hormones) or androgenic (male sex hormones) activity. (12 Dec 1998) |
| gonadal ridge | An elevation of thickened mesothelium and underlying mesenchyme on the ventromedial border of the embryonic mesonephros; the primordial germ cells become embedded in it, establishing it as the primordium of the testis or ovary. Synonym: genital ridge. (05 Mar 2000) |
| gonadal steroid-binding globulin | A protein that transports 65% of the testosterone in plasma. Synonym: sex steroid-binding globulin. (05 Mar 2000) |
| male gonad | <anatomy> One of the two male reproductive glands located in the cavity of the scrotum. The testes produce sperm and male sex hormones. (13 Nov 1997) |
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| streak gonad | A form of aplasia in which the ovary is replaced by a functionless tissue, as found in Turner's syndrome. Synonym: streak gonad. (05 Mar 2000) |
| suspensory ligament of gonad | <anatomy> An embryonic mesenchymatous band providing support for the internal genitalia. Synonym: suspensory ligament of gonad. (05 Mar 2000) |
| indifferent gonad | The primordial organ in an embryo before its differentiation into testis or ovary. See: indifferent genitalia. (05 Mar 2000) |
| female gonad | <anatomy> One of two small oval bodies situated on either side of the uterus on the posterior surface of the broad ligament. The structures in which the ova (eggs) are developed and released during ovulation. (05 Jan 1998) |