Difference between revisions of "Internal and External Genitalia Development - Anatomy & Physiology"
Jump to navigation
Jump to search
Fiorecastro (talk | contribs) |
Amycartmel (talk | contribs) (New page: ==Introduction== = Internal Genetalia = * Male: '''Wolffian Duct''' developes from the '''Mesonephric Duct''' * Female: '''Mullarian Ducts''' develop from the '''Paramesonephric Duct''' ...) |
||
| (24 intermediate revisions by 6 users not shown) | |||
| Line 1: | Line 1: | ||
| + | ==Introduction== | ||
| − | |||
| − | |||
| − | = Internal | + | = Internal Genetalia = |
| − | + | * Male: '''Wolffian Duct''' developes from the '''Mesonephric Duct''' | |
| − | * Male: | + | * Female: '''Mullarian Ducts''' develop from the '''Paramesonephric Duct''' |
| − | * Female: | ||
* This is dependent on appropriate hormonal influence. | * This is dependent on appropriate hormonal influence. | ||
| Line 14: | Line 12: | ||
| − | * '''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 genetalia. |
| − | * '''Androgens''' actively maintain '''Wolffian Ducts''', which give rise to male internal | + | * '''Androgens''' actively maintain '''Wolffian Ducts''', which give rise to male internal genetalia: |
** Epididymis | ** Epididymis | ||
** Vas Deferens | ** Vas Deferens | ||
** Vesicular Glands/ Seminal Vesicles | ** Vesicular Glands/ Seminal Vesicles | ||
| − | * '''MIH''' causes | + | * '''MIH''' causes Mullarian Ducts to regress |
| + | |||
== Female == | == Female == | ||
| − | * Wolffian Ducts spontaneously regress in | + | * Wolffian Ducts spontaneously regress in absence of Androgens. |
| − | * '''Mullarian Ducts''' persist to give rise to female internal | + | * '''Mullarian Ducts''' persist to give rise to female internal genetalia: |
** 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 genetalia. |
---- | ---- | ||
| − | = External | + | = External Genetalia = |
| − | + | ||
== Male == | == Male == | ||
| − | * Potential to develop male | + | * Potential to develop male of female external genetalia. '''Testosterone''' is required to develop male external genetalia. |
* 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''' | ||
| + | |||
| + | |||
== Female == | == Female == | ||
| Line 51: | Line 52: | ||
| − | * Exposure of the female tract to Androgens will masculinise external | + | * Exposure of the female tract to Androgens will masculinise external genetalia. |
* 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. | ||
---- | ---- | ||
| − | = | + | = Sexual Differentiation of the Brain = |
| + | |||
| + | |||
| + | == Male == | ||
| + | |||
| + | * '''Testosterone''' secreted into the blood reaches the brain. | ||
| + | * Converted to Dehydrotestosterone and '''Oestradiol''' by Aromatase enzymes in the Hypothalamus. | ||
| + | * Oestradiol masculinises the brain | ||
| + | |||
| + | |||
| + | == Female == | ||
| + | * '''Alpha Fetoprotein''' binds Oestradiol, preventing it from crossing the blood-brain barrier. | ||
| + | * Oestradiol cannot access the Hypothalamus | ||
| + | * Protects female brain from masculising effects of Oestradiol. | ||
| + | ---- | ||
| − | + | = Associated Disorders = | |
| − | |||
| − | * [[ | + | * [[Fertilisation, Implantation and Early Embryonic Development -Turner's Syndrome - Anatomy & Physiology|Turner's Syndrome]] |
| − | * [[ | + | * [[Fertilisation, Implantation and Early Embryonic Development -Kleinfelter's Syndrome - Anatomy & Physiology|Kleinfelter's Syndrome]] |
| − | * [[ | + | * [[Fertilisation, Implantation and Early Embryonic Development -Testicular Feminisation - Anatomy & Physiology|Testicular Feminisation]] |
| − | * [[ | + | * [[Fertilisation, Implantation and Early Embryonic Development -Adrenogenital Syndrome - Anatomy & Physiology|Adrenogenital Syndrome]] |
| − | + | * [[Fertilisation, Implantation and Early Embryonic Development -Intersex - Anatomy & Physiology|Intersex]] | |
| − | |||
| − | [[ | + | * [[Fertilisation, Implantation and Early Embryonic Development -Bovine Freemartinism - Anatomy & Physiology|Bovine Freemartinism]] |
| − | |||
Revision as of 09:26, 11 August 2008
Introduction
Internal Genetalia
- Male: Wolffian Duct developes from the Mesonephric Duct
- Female: 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 genetalia.
- Androgens actively maintain Wolffian Ducts, which give rise to male internal genetalia:
- Epididymis
- Vas Deferens
- Vesicular Glands/ Seminal Vesicles
- MIH causes Mullarian Ducts to regress
Female
- Wolffian Ducts spontaneously regress in absence of Androgens.
- Mullarian Ducts persist to give rise to female internal genetalia:
- Oviducts
- Uterus
- Cervix
- Cranial Vagina
- Normal Ovarian activity is NOT essential for the development of normal female internal genetalia.
External Genetalia
Male
- Potential to develop male of female external genetalia. Testosterone is required to develop male external genetalia.
- 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 genetalia.
- Failure of proper endocrine communication between the gonads, internal and external genitalia can lead to dissociation of gonadal and genital sex.
Sexual Differentiation of the Brain
Male
- Testosterone secreted into the blood reaches the brain.
- Converted to Dehydrotestosterone and Oestradiol by Aromatase enzymes in the Hypothalamus.
- Oestradiol masculinises the brain
Female
- Alpha Fetoprotein binds Oestradiol, preventing it from crossing the blood-brain barrier.
- Oestradiol cannot access the Hypothalamus
- Protects female brain from masculising effects of Oestradiol.