# Gonad

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Gland that produces sex cells

For the cartoon character, see [Buster Gonad](/source/Buster_Gonad).

This article may require cleanup to meet Wikipedia's quality standards. The specific problem is: Writing does not cover the subject in a clear and concise manner. Please help improve this article if you can. (May 2012) (Learn how and when to remove this message)

Gonad A pair of ovaries of Cyprinus carpio (common carp) placed in dissecting dish Identifiers MeSH D006066 FMA 18250 Anatomical terminology [edit on Wikidata]

A **gonad**, **sex gland**, or **reproductive gland**[1] is a [mixed gland](/source/Heterocrine_gland) and [sex organ](/source/Sex_organ) that produces the [gametes](/source/Gamete) and [sex hormones](/source/Sex_hormone) of an organism. [Female](/source/Female) reproductive cells are [egg cells](/source/Egg_cell), and [male](/source/Male) reproductive cells are [sperm](/source/Sperm).[2] The male gonad, the [testicle](/source/Testicle), produces sperm in the form of [spermatozoa](/source/Spermatozoon). The female gonad, the [ovary](/source/Ovary), produces egg cells. Both of these gametes are [haploid](/source/Haploid) cells. Some [hermaphroditic](/source/Hermaphroditic) animals (and some humans‍— see [Ovotesticular syndrome](/source/Ovotesticular_syndrome)) have a type of gonad called an [ovotestis](/source/Ovotestis).

## Evolution

Main article: [Evolution of sexual reproduction](/source/Evolution_of_sexual_reproduction)

It is hard to find a common origin for gonads, but gonads most likely [evolved independently](/source/Evolved_independently) several times.[3]

## Regulation

The gonads are controlled by [luteinizing hormone](/source/Luteinizing_hormone) (LH) and [follicle-stimulating hormone](/source/Follicle-stimulating_hormone) (FSH), produced and secreted by [gonadotropes or gonadotrophins](/source/Gonadotropic_cell) in the [anterior pituitary gland](/source/Anterior_pituitary_gland).[4] This secretion is regulated by [gonadotropin-releasing hormone](/source/Gonadotropin-releasing_hormone) (GnRH) produced in the [hypothalamus](/source/Hypothalamus).[5][6]

## Development

Main article: [Development of the gonads](/source/Development_of_the_gonads)

The gonads develop from three sources; the mesothelium, underlying mesenchyme and the primordial germ cells. Gonads start developing as a common primordium (an organ in the earliest stage of development), in the form of [genital ridges](/source/Genital_ridge),[7] at the sixth week, which are only later [differentiated](/source/Sexual_differentiation) to male or female [sex organs](/source/Sex_organ) (except when they are not differentiated). The presence of the [SRY](/source/SRY) [gene](/source/Gene),[8] located on the short arm of the [Y chromosome](/source/Y_chromosome) and encoding the [testis determining factor](/source/Testis_determining_factor), usually determines male sexual differentiation. In the absence of the SRY gene from the Y chromosome, usually the female sex (ovaries instead of testes) will develop. The [development of the gonads](/source/Development_of_the_gonads) is a part of the [development of the urinary and reproductive organs](/source/Development_of_the_urinary_and_reproductive_organs).[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

## Disease

This section needs expansion. You can help by adding missing information. (September 2022)

The gonads are subject to many diseases, such as [hypergonadism](/source/Hypergonadism), [hypogonadism](/source/Hypogonadism), [agonadism](/source/Agonadism), tumors, and cancer, among others.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

## Aging

### Ovarian aging

A delay in having children is common in the developed world and this delay is often associated with ovarian [female infertility](/source/Female_infertility) and subfertility. Ovarian aging is characterized by progressive decline of the quality and number of [oocytes](/source/Oocyte).[9] This decline is likely due, in part, to reduced expression of genes that encode proteins necessary for [DNA repair](/source/DNA_repair) and [meiosis](/source/Meiosis).[10][11] Such reduced expression can lead to increased [DNA damage](/source/DNA_damage_(naturally_occurring)) and errors in meiotic [recombination](/source/Homologous_recombination).[9]

### Testicular aging

The testes of older men often have [sperm](/source/Sperm) abnormalities that can ultimately lead to [male infertility](/source/Male_infertility).[12] These abnormalities include accumulation of DNA damage and decreased DNA repair ability.[12] During spermatogenesis in the testis, spontaneous new mutations arise and tend to accumulate with age.[13]

## See also

- [Anatomy portal](https://en.wikipedia.org/wiki/Portal:Anatomy)

- [Gonadosomatic index](/source/Gonadosomatic_index)

- [Hypothalamic–pituitary–gonadal axis](/source/Hypothalamic%E2%80%93pituitary%E2%80%93gonadal_axis)

## References

1. **[^](#cite_ref-1)** ["the definition of sex gland"](http://dictionary.reference.com/browse/sex+gland?r=66). *Dictionary.com*. [Archived](https://web.archive.org/web/20150722180541/http://dictionary.reference.com/browse/sex+gland?r=66) from the original on 22 July 2015. Retrieved 8 May 2018.

1. **[^](#cite_ref-2)** ["gonad (noun) American English definition and synonyms - Macmillan Dictionary"](http://www.macmillandictionary.com/dictionary/american/gonad). *www.macmillandictionary.com*. [Archived](https://web.archive.org/web/20180508154610/http://www.macmillandictionary.com/dictionary/american/gonad) from the original on 8 May 2018. Retrieved 8 May 2018.

1. **[^](#cite_ref-3)** Schmidt-Rhaesa, Andreas (2007-08-30). ["13. Reproductive organs"](https://books.google.com/books?id=iiwTDAAAQBAJ&pg=PA252). *The Evolution of Organ Systems*. Oxford University Press. p. 252. [ISBN](/source/ISBN_(identifier)) [978-0-19-856668-7](https://en.wikipedia.org/wiki/Special:BookSources/978-0-19-856668-7). [OCLC](/source/OCLC_(identifier)) [190852859](https://search.worldcat.org/oclc/190852859). The diversity of modes in which gonads are formed makes it hard to substantiate a common origin of gonads. It appears to be more likely that gonads evolved independently several times.

1. **[^](#cite_ref-4)** ["gonadotropin"](http://medical-dictionary.thefreedictionary.com/gonadotropin). *The Free Dictionary*. Mosby's Medical Dictionary, 8th edition. Elsevier. 2009. Retrieved 4 June 2012.

1. **[^](#cite_ref-5)** Kimball, John W. (12 February 2011). ["Hormones of the Hypothalamus: Gonadotropin-releasing hormone (GnRH)"](https://web.archive.org/web/20120627085615/http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/H/Hypothalamus.html#GnRH). *Kimball's Biology Pages*. John W. Kimball (The Saylor Foundation). Archived from [the original](http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/H/Hypothalamus.html#GnRH) on 27 June 2012. Retrieved 4 June 2012.

1. **[^](#cite_ref-Marieb_6-0)** Marieb, Elaine (2013). *Anatomy & physiology*. Benjamin-Cummings. p. 915. [ISBN](/source/ISBN_(identifier)) [978-0-321-88760-3](https://en.wikipedia.org/wiki/Special:BookSources/978-0-321-88760-3). [OCLC](/source/OCLC_(identifier)) [43903780](https://search.worldcat.org/oclc/43903780).

1. **[^](#cite_ref-Larsen1_7-0)** Schoenwolf, Gary C. (2015). *Larsen's human embryology* (5th ed.). Elsevier. p. 16. [ISBN](/source/ISBN_(identifier)) [978-1-4557-0684-6](https://en.wikipedia.org/wiki/Special:BookSources/978-1-4557-0684-6). [OCLC](/source/OCLC_(identifier)) [862800082](https://search.worldcat.org/oclc/862800082).

1. **[^](#cite_ref-8)** ["Human Developmental Genetics"](https://web.archive.org/web/20120505080019/http://www.pasteur.fr/ip/easysite/pasteur/en/research/scientific-departments/developmental-biology/units-and-groups/human-developmental-genetics). *Institut Pasteur*. Archived from [the original](http://www.pasteur.fr/ip/easysite/pasteur/en/research/scientific-departments/developmental-biology/units-and-groups/human-developmental-genetics) on 5 May 2012. Retrieved 4 June 2012.

1. ^ [***a***](#cite_ref-Park2021_9-0) [***b***](#cite_ref-Park2021_9-1) Park SU, Walsh L, Berkowitz KM (July 2021). ["Mechanisms of ovarian aging"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9354567). *Reproduction*. **162** (2): R19–R33. [doi](/source/Doi_(identifier)):[10.1530/REP-21-0022](https://doi.org/10.1530%2FREP-21-0022). [PMC](/source/PMC_(identifier)) [9354567](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9354567). [PMID](/source/PMID_(identifier)) [33999842](https://pubmed.ncbi.nlm.nih.gov/33999842).

1. **[^](#cite_ref-10)** Yang Q, Mumusoglu S, Qin Y, Sun Y, Hsueh AJ (August 2021). ["A kaleidoscopic view of ovarian genes associated with premature ovarian insufficiency and senescence"](https://doi.org/10.1096%2Ffj.202100756R). *FASEB J*. **35** (8) e21753. [doi](/source/Doi_(identifier)):[10.1096/fj.202100756R](https://doi.org/10.1096%2Ffj.202100756R). [PMID](/source/PMID_(identifier)) [34233068](https://pubmed.ncbi.nlm.nih.gov/34233068).

1. **[^](#cite_ref-11)** Turan V, Oktay K (January 2020). ["BRCA-related ATM-mediated DNA double-strand break repair and ovarian aging"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6935693). *Hum Reprod Update*. **26** (1): 43–57. [doi](/source/Doi_(identifier)):[10.1093/humupd/dmz043](https://doi.org/10.1093%2Fhumupd%2Fdmz043). [PMC](/source/PMC_(identifier)) [6935693](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6935693). [PMID](/source/PMID_(identifier)) [31822904](https://pubmed.ncbi.nlm.nih.gov/31822904).

1. ^ [***a***](#cite_ref-Dong2022_12-0) [***b***](#cite_ref-Dong2022_12-1) Dong S, Chen C, Zhang J, Gao Y, Zeng X, Zhang X (2022). ["Testicular aging, male fertility and beyond"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9606211). *Front Endocrinol (Lausanne)*. **13** 1012119. [doi](/source/Doi_(identifier)):[10.3389/fendo.2022.1012119](https://doi.org/10.3389%2Ffendo.2022.1012119). [PMC](/source/PMC_(identifier)) [9606211](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9606211). [PMID](/source/PMID_(identifier)) [36313743](https://pubmed.ncbi.nlm.nih.gov/36313743).

1. **[^](#cite_ref-13)** Cioppi F, Casamonti E, Krausz C (2019). "Age-Dependent De Novo Mutations During Spermatogenesis and Their Consequences". *Genetic Damage in Human Spermatozoa*. Adv Exp Med Biol. Vol. 1166. pp. 29–46. [doi](/source/Doi_(identifier)):[10.1007/978-3-030-21664-1_2](https://doi.org/10.1007%2F978-3-030-21664-1_2). [ISBN](/source/ISBN_(identifier)) [978-3-030-21663-4](https://en.wikipedia.org/wiki/Special:BookSources/978-3-030-21663-4). [PMID](/source/PMID_(identifier)) [31301044](https://pubmed.ncbi.nlm.nih.gov/31301044).

v t e Anatomy of the endocrine system Pituitary gland Anterior Pars intermedia Pars tuberalis Pars distalis Acidophil cell Somatotropic cell Prolactin cell Somatomammotrophic cell Basophil cell Corticotropic cell Gonadotropic cell Thyrotropic cell Chromophobe cell Posterior Pars nervosa Median eminence Stalk Pituicyte Herring bodies Thyroid Follicular cell Parafollicular cell Parathyroid gland Chief cell Oxyphil cell Adrenal gland Cortex Zona glomerulosa Zona fasciculata Zona reticularis Medulla Chromaffin cell Gonads Testicle Leydig cell Sertoli cell Ovary Theca interna Granulosa cell Corpus luteum Islets of pancreas Alpha cell Beta cell PP cell Delta cell Epsilon cell Pineal gland Pinealocyte Corpora arenacea Other Enteroendocrine cell Paraganglia Organ of Zuckerkandl Placenta Development List of human endocrine organs and actions

Authority control databases International GND National United States France BnF data Czech Republic Israel Other Yale LUX

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Adapted from the Wikipedia article [Gonad](https://en.wikipedia.org/wiki/Gonad) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Gonad?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.