Difference between revisions of "Internal and External Genitalia Development - Anatomy & Physiology"
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==Introduction== | ==Introduction== | ||
| − | Sexual | + | Sexual differentiaton by default follows a pathways for development of female internal and external genitalia, requiring no active intervention. Endocrine activity of the testes, production of Androgens by Leydig cells and Mullerian Inhibiting hormone (MIH) by Sertoli cells, is required for sexual differentiation to be diverted down the male genitalia development pathway. |
| − | = Internal | + | = Internal Genitalia = |
From the primitive reproductive tracts the Internal genitalia can only develop into one gender and so are termed unipotent. | From the primitive reproductive tracts the Internal genitalia can only develop into one gender and so are termed unipotent. | ||
* Male: The primitive male reproductive tract '''The Wolffian Duct''' developes from the '''Mesonephric Duct''' | * Male: The primitive male reproductive tract '''The Wolffian Duct''' developes from the '''Mesonephric Duct''' | ||
| Line 16: | Line 14: | ||
| − | * '''MIH''' from '''Sertoli cells''' and '''Androgens''' from '''Leydig cells''' prevent spontaneous development of female internal | + | * '''MIH''' from '''Sertoli cells''' and '''Androgens''' from '''Leydig cells''' prevent spontaneous development of female internal genitalia. |
| − | * '''Androgens''' actively maintain '''Wolffian Ducts''', which give rise to male internal | + | * '''Androgens''' actively maintain '''Wolffian Ducts''', which give rise to male internal genitalia: |
** Epididymis | ** Epididymis | ||
** Vas Deferens | ** Vas Deferens | ||
** Vesicular Glands/ Seminal Vesicles | ** Vesicular Glands/ Seminal Vesicles | ||
| − | * '''MIH''' causes the primitive female reproductive tract | + | * '''MIH''' causes the primitive female reproductive tract Mullerian Ducts to regress. |
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== Female == | == Female == | ||
* Wolffian Ducts spontaneously regress in the absence of Androgens. | * Wolffian Ducts spontaneously regress in the absence of Androgens. | ||
| − | * '''Mullarian Ducts''' persist to give rise to female internal | + | * '''Mullarian Ducts''' persist to give rise to female internal genitalia: |
** Oviducts | ** Oviducts | ||
** Uterus | ** Uterus | ||
** Cervix | ** Cervix | ||
** Cranial Vagina | ** Cranial Vagina | ||
| − | * Normal Ovarian activity is NOT essential for the development of normal female internal | + | * Normal Ovarian activity is NOT essential for the development of normal female internal genitalia as this is the default development pathway. |
---- | ---- | ||
| − | = External | + | = External Genitalia = |
| − | External genitalia have the | + | External genitalia have the potential to be either gender and so are bipotential. |
== Male == | == Male == | ||
| − | * Potential to develop male or female external | + | * Potential to develop male or female external genitalia. '''Testosterone''' is required to develop male external genitalia. |
* Androgen secretion from the Testes induces: | * Androgen secretion from the Testes induces: | ||
** '''Urethral folds''' to fuse to allow enclosure of the urethral tube. This, together with the cells from the '''genital swelling''', forms the '''shaft of the Penis'''. | ** '''Urethral folds''' to fuse to allow enclosure of the urethral tube. This, together with the cells from the '''genital swelling''', forms the '''shaft of the Penis'''. | ||
** '''Genital swellings''' fuse in the midline to allow formation of the '''Scrotum''' | ** '''Genital swellings''' fuse in the midline to allow formation of the '''Scrotum''' | ||
** '''Genital Tubercle''' expands to give rise to the '''Glans Penis''' | ** '''Genital Tubercle''' expands to give rise to the '''Glans Penis''' | ||
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== Female == | == Female == | ||
| Line 56: | Line 51: | ||
| − | * Exposure of the female tract to Androgens will masculinise external | + | * Exposure of the female tract to Androgens will masculinise external genitalia. |
* Failure of proper endocrine communication between the gonads, internal and external genitalia can lead to '''dissociation''' of gonadal and genital sex. | * Failure of proper endocrine communication between the gonads, internal and external genitalia can lead to '''dissociation''' of gonadal and genital sex. | ||
| Line 64: | Line 59: | ||
| − | * [[ | + | * [[Turner's Syndrome|Turner's Syndrome]] |
| + | |||
| + | * [[Kleinfelter's Syndrome|Kleinfelter's Syndrome]] | ||
| + | |||
| + | * [[Testicular Feminisation|Testicular Feminisation]] | ||
| − | * [[ | + | * [[Adrenogenital Syndrome|Adrenogenital Syndrome]] |
| − | * [[ | + | * [[Intersex|Intersex]] |
| − | * [[ | + | * [[Bovine Freemartinism|Bovine Freemartinism]] |
| − | + | ==Webinars== | |
| + | <rss max="10" highlight="none">https://www.thewebinarvet.com/urogenital-and-reproduction/webinars/feed</rss> | ||
| − | + | [[Category:Male Reproduction]][[Category:Female Reproduction]][[Category:Developmental Biology]] | |
| + | [[Category:Bullet Points]] | ||
Latest revision as of 16:11, 5 January 2023
Introduction
Sexual differentiaton by default follows a pathways for development of female internal and external genitalia, requiring no active intervention. Endocrine activity of the testes, production of Androgens by Leydig cells and Mullerian Inhibiting hormone (MIH) by Sertoli cells, is required for sexual differentiation to be diverted down the male genitalia development pathway.
Internal Genitalia
From the primitive reproductive tracts the Internal genitalia can only develop into one gender and so are termed unipotent.
- Male: The primitive male reproductive tract The Wolffian Duct developes from the Mesonephric Duct
- Female: The primitive female reproductive tract Mullarian Ducts develop from the Paramesonephric Duct
- This is dependent on appropriate hormonal influence.
Male
- MIH from Sertoli cells and Androgens from Leydig cells prevent spontaneous development of female internal genitalia.
- Androgens actively maintain Wolffian Ducts, which give rise to male internal genitalia:
- Epididymis
- Vas Deferens
- Vesicular Glands/ Seminal Vesicles
- MIH causes the primitive female reproductive tract Mullerian Ducts to regress.
Female
- Wolffian Ducts spontaneously regress in the absence of Androgens.
- Mullarian Ducts persist to give rise to female internal genitalia:
- Oviducts
- Uterus
- Cervix
- Cranial Vagina
- Normal Ovarian activity is NOT essential for the development of normal female internal genitalia as this is the default development pathway.
External Genitalia
External genitalia have the potential to be either gender and so are bipotential.
Male
- Potential to develop male or female external genitalia. Testosterone is required to develop male external genitalia.
- Androgen secretion from the Testes induces:
- Urethral folds to fuse to allow enclosure of the urethral tube. This, together with the cells from the genital swelling, forms the shaft of the Penis.
- Genital swellings fuse in the midline to allow formation of the Scrotum
- Genital Tubercle expands to give rise to the Glans Penis
Female
- Development is ensured by the absence of Testosterone, it is independent of Ovarian endocrine activity.
- Urethral folds and Genital Swellings remain separate to form the Labia Minora and Majora.
- Genital tubercle forms the Clitoris
- Exposure of the female tract to Androgens will masculinise external genitalia.
- Failure of proper endocrine communication between the gonads, internal and external genitalia can lead to dissociation of gonadal and genital sex.
Associated Disorders
Webinars
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