Sexual development Flashcards
XX chromosome
Female
XY chromosome
Male
0-6 weeks
0-6 weeks
Male and female embryos develop in the same way
-Embryo contains precursor tissue which can develop into either male or female gonads
-Male and female internal reproductive ducts
Precursor tissue: Cortex of primordial gonads
Can turn into ovaries
Precursor tissue: Medulla of primordial gonads
Can turn into testes
Wolfian system
-Precursor to male reproductive system
-Contains seminal vesciles and -Vas deferens (duct from testes to penis)
Mullerian System
Precursor to female reproductive system-uterus, upper vagina and fallopian tubes
6 weeks
6 Weeks
-SRY (sex determining region y gene) sets in motion events which lead to sexual differentiation
SRY gene produces the H-Y antigen which differentiates foetal testes resulting in the medulla of primordal gonads developing into testes
SRY (Sex determining region y gene)
Determines sexual differentiation, will sometimes produce H-Y antigen which results in the development of a male reproductive system around 6 weeks
h-Y antigen
Sometimes produced around 6 weeks and results in the medulla of primordial gonads turning into testes
If this antigen is not present, overaies will develop and the child will be a girl.
Weeks 9-12
-Sexual organs begin to develop from primordinal tissues Androgens such as dihydrotestosterone are produced in male testes which stimulates male sexual organ development but not in females
dihydrotestosterone
Stimulate development of male reproductive system in embyros
Weeks 12+
In male foetal development, testes produce
-Mullerian Inhibiting Hormone- causes the mullerian system to degenerate and the testes to descend into the scrotum
-Androgens which stimulate the development of the wolfian system
