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Sexual Differentiation - Anatomy & Physiology (view source)
Revision as of 09:20, 3 July 2008
, 09:20, 3 July 2008→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''').
* The X sex chromasome is larger than the Y sex chromasome.
* The X sex chromosome is larger than the Y sex chromosome.
* '''Females''' have XX chromasomes. All oocytes contain one X chromasome, they are the '''homogametic''' sex.
* '''Females''' have XX chromosomes. All oocytes contain one X chromosome, they are the '''homogametic''' sex.
* '''Males''' have XY chromasomes. Spermatozoa form two distinct populations, one containing X chromasomes and one containing Y chromasomes. They are the '''heterogametic''' sex.
* '''Males''' have XY chromosomes. Spermatozoa form two distinct populations, one containing X chromosomes and one containing Y chromosomes. They are the '''heterogametic''' sex.
* The '''Y''' chromosome is required to '''initiate male development'''.
* In absence of the Y chromosome, female gonads (Ovaries) will develop.
* The prime male determining gene is '''SRY''' (sex determining region of the Y chromosome). SRY is a very small piece of DNA that acts as a molecular switch to regulate structural genes and autosomal chromosomes
* The presence of SRY alone is sufficient to ensure development of male gonads (Testes).
== Internal Genetalia ==
== Internal Genetalia ==