Difference between revisions of "Sexual Differentiation - Anatomy & Physiology"
Jump to navigation
Jump to search
Line 44: | Line 44: | ||
− | ::[[Fertilisation, Implantation and Early Embryonic Development - | + | ::[[Fertilisation, Implantation and Early Embryonic Development -Turner's Syndrome - Anatomy & Physiology|Turner's Syndrome]] |
− | ::[[Fertilisation, Implantation and Early Embryonic Development - | + | ::[[Fertilisation, Implantation and Early Embryonic Development -Kleinfelter's Syndrome - Anatomy & Physiology|Kleinfelter's Syndrome]] |
− | ::[[Fertilisation, Implantation and Early Embryonic Development - | + | ::[[Fertilisation, Implantation and Early Embryonic Development -Testicular Feminisation - Anatomy & Physiology|Testicular Feminisation]] |
− | ::[[Fertilisation, Implantation and Early Embryonic Development - | + | ::[[Fertilisation, Implantation and Early Embryonic Development -Adrenogenital Syndrome - Anatomy & Physiology|Adrenogenital Syndrome]] |
− | ::[[Fertilisation, Implantation and Early Embryonic Development - | + | ::[[Fertilisation, Implantation and Early Embryonic Development -Hermaphroditism - Anatomy & Physiology|Hermaphroditism]] |
− | ::[[Fertilisation, Implantation and Early Embryonic Development - | + | ::[[Fertilisation, Implantation and Early Embryonic Development -Bovine Freemartinism - Anatomy & Physiology|Bovine Freemartinism]] |
Revision as of 09:38, 3 July 2008
Genetic Sex
- 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 X sex chromosome is larger than the Y sex chromosome.
- Females have XX chromosomes. All oocytes contain one X chromosome, they are the homogametic 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, determining if and when they are to be activated.
- The presence of SRY alone is sufficient to ensure development of male gonads (Testes).
- Female is the default sex, in absence of SRY female gonads (Ovaries) will develop.
- Subsequent gonadal development is dependent on a normal population of germ cells.
- Normal Oocyte growth requires the activity of both X chromosomes.