Difference between revisions of "Sexual Differentiation - Anatomy & Physiology"
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− | + | == Genetic Sex == | |
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− | = 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 (''' | + | * 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. | * 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. | * '''Females''' have '''XX''' chromosomes. All oocytes contain one X chromosome, they are the '''homogametic''' sex. | ||
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* The '''Y''' chromosome is required to '''initiate male development'''. | * The '''Y''' chromosome is required to '''initiate male development'''. | ||
− | * In absence of the Y chromosome, female gonads ( | + | * 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 | + | * 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. | * 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). | |
− | * The presence of SRY alone is sufficient to ensure development of male gonads ( | + | * Female is the default sex, in absence of SRY female gonads (Ovaries) will develop. |
− | * Female is the default sex, in absence of SRY female gonads ( | ||
* Subsequent gonadal development is dependent on a normal population of '''germ cells'''. | * Subsequent gonadal development is dependent on a normal population of '''germ cells'''. | ||
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− | + | == Internal Genetalia == | |
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+ | == External Genetalia == | ||
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− | + | ::[[Fertilisation, Implantation and Early Embryonic Development -Sexual Differentiation - Anatomy & Physiology|Turner's Syndrome]] | |
− | + | ::[[Fertilisation, Implantation and Early Embryonic Development -Sexual Differentiation - Anatomy & Physiology|Kleinfelter's Syndrome]] | |
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+ | ::[[Fertilisation, Implantation and Early Embryonic Development -Sexual Differentiation - Anatomy & Physiology|Testicular Feminisation]] | ||
+ | ::[[Fertilisation, Implantation and Early Embryonic Development -Sexual Differentiation - Anatomy & Physiology|Adrenogenital Syndrome]] | ||
− | [[ | + | ::[[Fertilisation, Implantation and Early Embryonic Development -Sexual Differentiation - Anatomy & Physiology|Bovine Freemartinism]] |
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Revision as of 09:23, 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.