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12 Cards in this Set
- Front
- Back
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What is Jost's Model of Sexual Differentiation?
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Genetic Sex ----> Gonadal Sex ----> Phenotypic Sex
The arrow between gonads and phenotype consists of hormones Also, there are sometime direct connections between Genes and phenotype |
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What determines gonadal sex?
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The germinal ridge becomes the testes or the ovaries.
If the organism has a Y chromosome with SRY gene, SRY will code for testes determining factor, which will cause growth of testes. If no SRY, then no TDF, then ovaries. |
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What 2 systems are initially present in each embryo?
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Wolffian ducts, and Mullerian ducts
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What affects Wolffian duct formation? Mullerian duct formation?
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Presence/Absence of Testosterone affects Wolffian duct formation.
Presence/Absence of MIH affects Mullerian duct formation. |
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What determines differentiation of external genitalia?
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DHT. DHT leads to formation of a penis.
no testes, no testosterone, no DHT, no penis. |
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What is true hermaphrodism?
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Having both ovaries and testes
For example, having ovaries on one side and testis on the other |
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What is Turner's syndyome?
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XO chromosome. This causes high GnRH levels in infancy and post pubertally. These people are often short and have immature genitalia and reproductive tracts.
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What is Congenital Adrenal Hyperplasia?
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CAH, it is when precursors for aldosterone and cortisol can't be converted to the next step in the pathway, and build up, eventually getting shunted into the androgen pathway and producing high amounts of androgens.
Thus masculinization of the external genitalia starts occurring. (Androgens determine external genitalia, TDF determines internal workings). This can be fixed with surgery and exogenous hormones. |
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What is Androgen Insensitivity Syndrome?
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This is where an x-linked gene has a defective androgen receptor. Thus the person has an XY genome, but a female appearance with female external genitalia. Also, testes develop because of SRY gene and TDF.
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What if there is a 5 alpha reductase deficiency?
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If the person is chromosomal male (XY), they will have internal testes and wolffian ducts. But the external genitalia will be female because there is not enough DHT. But at puberty, there is so much testosterone produced that DHT gets made anyways. The person then sprouts a penis.
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What is klinefelter syndrome?
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A person with XXY.
This person has androgen deficiency, low intelligence, and low intelligence. |
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What is the other trisomy disorder?
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A person with XYY. They are extremely tall, stupid, and antisocial, but sexually they develop normally.
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