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Internal and External Genitalia Development - Anatomy & Physiology (view source)
Revision as of 09:26, 11 August 2008
, 09:26, 11 August 2008New page: ==Introduction== = Internal Genetalia = * Male: '''Wolffian Duct''' developes from the '''Mesonephric Duct''' * Female: '''Mullarian Ducts''' develop from the '''Paramesonephric Duct''' ...
==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.
----
= 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]]
= 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.
----
= 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]]