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Sexual Differentiation - Anatomy & Physiology (view source)
Revision as of 12:22, 21 July 2008
, 12:22, 21 July 2008→Genetic Sex
= Genetic Sex =
* Established at the time of '''fertilisation'''.
* Established at the time of '''fertilisation'''.
* The foetus receives its genetic endowment in two equal portions from the male gamete ('''Spermatozoon''') and female gamete ('''Oocyte''').
* The foetus receives its genetic endowment in two equal portions from the male gamete ('''Spermatozoon''') and female gamete ('''Oocyte''').
== Male ==
* Sex cord cells proliferate to form the testes cord. During this period '''SRY''' is expressed for the first time within '''Sertoli cells''' (SRY is NOT expressed in primordial germ cells).
* Sex cord cells proliferate to form the testes cord. During this period '''SRY''' is expressed for the first time within '''Sertoli cells''' (SRY is NOT expressed in primordial germ cells).
== Female ==
* At the time the male gonad is undergoing marked changes under the direction of SRY, the female gonad continues to appear indifferent and does not express SRY.
* At the time the male gonad is undergoing marked changes under the direction of SRY, the female gonad continues to appear indifferent and does not express SRY.
== Foetal sex differentiation ==
* Endocrine activity of the Ovaries is NOT essential for sex differentiation during foetal life, abnormal ovarian development will have no effect until puberty.
* Endocrine activity of the Ovaries is NOT essential for sex differentiation during foetal life, abnormal ovarian development will have no effect until puberty.
* Testes secrete two essential hormones:
* Testes secrete two essential hormones:
* In absence of these testicular hormones, female differentiation occurs.
* In absence of these testicular hormones, female differentiation occurs.
* Thus, sexual differentiation must be actively diverted down the male route, the female route requires no active intervention.
* Thus, sexual differentiation must be actively diverted down the male route, the female route requires no active intervention.
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