4.8 Endocrine male Flashcards
5 significant hormones of male reproduction?
1) testosterone
2) follicle stimulating hormone
3) luteinising hormone
4) human chorionic gonadotropin
5) inhibin
testosterone chemical neture and source?
- steroid
* Leydig cells of testes= ‘interstitial cells’ between seminiferous tubules
for the first 40 days (6 weeks) an embryo has ______ gonads
undifferenciated
at six week either:
– development of cortex= no TDF =ovaries
– devel of medulla= yes TDF = testes
what gene serves as a testes-determining factor (TDF)?
SRY (sex-determining region) on Y chromosome serves as testes-detemining factor
absence of TDF means?
ovaries will develop
1) testosterone secretion begins?
2) peaks?
3) declines
4) levels rise again?
1) begins as early as 8 weeks after conception
2) peak at 12-14 weeks
3) declines to very low levels at 25 weeks
- -when delivered, equal for both genders
4) rise again at puberty
what is testosterone 2 main functions?
1) sex differentiation (SRY and TDF)
2) descent of testes (later inpregnancy
1) must have testosterone for development of normal?
2) if absenct in male then devel of ___
3) if absent in male than devel of _____
genetalia
2) female genetalia
3) male genetalia
how is genetic sex determined?
by fertilization of ovum with sperm possessing Y or X chromosome
present of absense of ____ chromosome determiens if gonads are?
Y chromosome determines is gonads are testes or ovaries
17alpha hydroxylase is required for?
conversion of cholesteral to testosterone
*otherwise you’d have under-developed male infants
descent of testes promoted by?
testosterone and other factors like organs pushing testes down
testes must be at cooler temps such as 35 C instead of 37 why?
for spermatogenesis
define chryptorchidism
undescended testes = no spermatogenesis
*crypt= hidden; orchid= testes
undescended testes happen how often?
10% (usually 1) and higher in premies
- -2% by age 2
- -0.3% by puberty
why is treatment important for undescended testes?
1) for both spermatogenesis (sperm devel)
2) avoid heath complications like tumors
why must ndescended testes be surgically moved early?
after puberty, higher temps will cause irreverssible damage to spermatogenic epithelium AND increase risk of malignant tumors