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42 Cards in this Set
- Front
- Back
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weeks 1-6 |
primordial germ cells form in yolk sac -> migrate to gondal/genital ridge -> epithelial proliferation -> primitive sex cords |
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two ducts |
mesonephric and paramesonephric ducts |
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week 7 |
phenotypic sexual differentiation begins |
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week 12 |
external genitalia development |
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week 20 |
phenotypic differentiation complete |
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what does SRY encode? |
testes determining factor (TDF) |
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Sertoli cell development |
TDF stimulates primitive sex cords |
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Sertoli cells |
surround primordial germ cells, secrete androgen binding protein, secrete Mullerian inhibiting substance (paramesonephric degeneration) |
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Leydig cell development |
TDF -> mesenchyme b/t sex cords |
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what do leydig cells do? |
secrete testosterone (maintain mesonephric ducts), 5 alpha reductase makes DHT from testosterone (develop external male genitalia) |
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teste descent |
begin in abdomen -> go to scrotum; gubernaculum shortens & guides; peritoneum evaginates as processus vaginalis -> becomes tunica vaginalis |
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hypospadias |
urethral folds fail to fuse, urethral orifice opens on ventral surface of penis |
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epispadias |
urethral orifice opens on dorsal surface of penis; a/w exstrophy of the bladder |
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cryptorchidism |
failure of testes to descend, incr. risk of testicular carcinoma |
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what is most important in female development? |
lack of Y chromosome + presence of maternal estrogen! |
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primitive sex cords in females |
original degenerate; second migration wave forms primordial follicles (contain primary oocytes) -> form ovaries |
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somatic support cell fate in females |
follicular cells |
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no sertoli cells in females so... |
no MIS => paramesonephric ducts remain => migrate toward midline & fuse => form broad ligament, oviducts, uterus, upper vagina |
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no testosterone in females = |
mesonephric ducts degenerate |
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what does mother's estrogen do? |
develop female external genitalia |
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uterine fusion problems |
can lead to problems w/ implantation or menstruation |
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what does mesonephric duct form in males? |
epididymis, ductus deferens, seminal vesicle, ejaculatory duct |
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urogenital fold fate - females |
labia minora |
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urogenital fold fate - males |
ventral penis |
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labioscrotal swelling fate - females |
labia majora |
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labioscrotal swelling fate - males |
scrotum |
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gubernaculum fate - females |
ovarian ligament (superior), round ligament of uterus (inferior) |
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gubernaculum fate - males |
gubernaculum testes |
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male pseudohermaphrodism |
XY genotype + female phenotype; failure to make adequate tes. or DHT, complete androgen insensitivity, loss of MIS receptor |
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failure to make adequate test. or DHT |
5 alpha reductase deficient, 17 beta hydroxysteroid dehydrogenase => underdeveloped external genitalia & normal internal structures |
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complete androgen insensitivity |
mutated androgen receptor, doesn't respond to test. = female external genitalia, rudimentary vagina & tests in abdomen |
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female pseudohermaphrodism |
XX genotype + male phenotype; congenital adrenal hyperplasia |
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21-hydroxylase deficiency
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elevates androgens = masculinization of female fetus; no cortisol or aldo produced |
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Diethylstilbestrol (DES) |
synthetic nonsteroidal estrogen given to women in 1940-1970 - daughters exposed in utero at risk for vaginal tumors, clear cell carcinoma (T shaped uterus), sons developed hypospadias, cryptorchidism, incr. testicular cancer risk |
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bicornuate uterus |
partial fusion of paramesonephric ducts |
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didelphys uterus |
lack of fusion of paramesonephric ducts = double uterus |
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unicornuate uterus |
failure of paramesonephric ducts to develop |
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upper vagina derivation |
mesoderm |
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lower vagina derivation |
endoderm |
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remnants of mesonephric duct in females |
epoophoron, Paraoophoron, Gartner's cyst |
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development of prostate gland & bulbourethral gland |
derived from endoderm |
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remnants of paramesonephric ducts in male |
appendix testis & prostatic utricle |
