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gonad

 
Dictionary: go·nad   ('năd') pronunciation
n.
An organ in animals that produces gametes, especially a testis or ovary.

[New Latin gonas, gonad-, from Greek gonos, procreation, genitals.]

gonadal go·nad'al (gō-năd'l) or go·nad'ic adj.

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Dental Dictionary: gonad
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(gō′nad)
n

An ovary or testis, the site of origin of eggs or spermatozoa.

Science Dictionary: gonads
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(goh-nadz)

The organs in animals that produce sex cells: ovaries in the female, testes in the male.

A sex gland; a gamete-producing gland; the ovary in the female and the testis in the male.
The ovary produces the ovum and the testis produces the spermatozoon. In addition, the gonads secrete hormones that influence the development of the reproductive organs and the physical traits that differentiate males from females, such as a crest and body form and size (the secondary sex characters). The hormones produced by the ovary include estrogen and progesterone. The principal hormone produced by the testis is testosterone.

  • hermaphroditic g's — these gonads vary widely between combinations of male and female tissues in an ovotestis, of which there may be one or two, to a testicle on one side and an ovary on the other.
  • indifferent g. — the primordial stage of the embryonal gonad, before differentiation into a male or female organ.
Wikipedia: Gonad
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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.

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.

The development of gonads is a part of the harris development of the urinary and reproductive organs.


 
 

 

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Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.  Read more
Dental Dictionary. Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved.  Read more
Science Dictionary. The New Dictionary of Cultural Literacy, Third Edition Edited by E.D. Hirsch, Jr., Joseph F. Kett, and James Trefil. Copyright © 2002 by Houghton Mifflin Company. Published by Houghton Mifflin. All rights reserved.  Read more
Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Gonad" Read more