Genital embryology Flashcards
genitalia have male/female characteristics at….(when)
week 10
Genetic sex is defined by
Gonadal sex is defined by
genetic: sex chromosomes (males XY, females XX)
gonadal: precense of testes in males and ovaries in females
Phenotypic sex is defined by
the characteristics of internal genital tract and the external genitalia
default development - female vs male
female
genital embryology - female
default development
Mesonephric duct degenerates and paramesonephric (Mullerian) duct develops
mesonephric duct is AKA/function
Wolffian duct
- interim kidney for 1st trimester
- later contributes to male genital center (mesonephric duct)
genital embryology - male
SRY gene on Y chromosome produces testis-determining factor –> tests development –>
a. Sertoli cells –> Mullerian inhib factor (MIF)
- -> suppresses development of paramesonephric (Mullerian) ducts
b. Leyding cells secrete androgens that stimulate development of mesonphric duct
c. testosterone –> DHT –> genital tubercle, urogenital sinus –> male external genitalia, prostate
paramesonephric (Mullerian) duct in males
male –> sertoli cells secrete MIF that suppresses the development of paramesonephric (Mullerian) ducts –>
remnant as appendix testis
paramesonephric (Mullerian) duct in females
Develops into female internal structures - fallopian tubes, uterus, upper portion of vagina
(not lower portion of vagina - urogenital sinus)
Mesonephric (Wolffian) duct in males
Leyind cells secrete androgens –> stimulate development of mesonephric duct –> male internal structures (except prostate) - seminal vesicles, epididymis, Ejaculation duct, Ductus deferens
Mesonephric (Wolffian) duct in females
remnant as Gartner duct
Mullaerian agenesis is AKA
Mayer-Rokitansky-Kuster-Hauser syndrome
Mullaerian agenesis (Mayer-Rokitansky-Kuster-Hauser syndrome) - may present as
1ry amenorreha (due to lack of uterine development) in females with fully developed 2ry sexual characteristics)
no sertoli cells or lack Mullarian inhibitory - mechanism/presentation
no Mullaerian degeneration, normal action of testosterone –> develop both male and female internal genitalia and male characteristics
5α-reductase deficiency - mechanism/presentation
inability to convert Testosterone into DHT –> male internal genitalia (except prostate), ambiguous external genitalia until puberti (when increased testosterone levels cause masculinization)
5α-reductase deficiency - lab diagnosis
testosterone / DHT = 20 - 60 (normally 5)
Uterine (Mullerian duct) anomalies - types
- Septate uterus
- Bicornuate uterus
- Uterus didelphys
Septate uterus - mechanism/treatment
incomplete resoprtion of septum / septoplasty
Bicornuate uterus - mechanism
incomplete fusion of Mullerian ducts
Uterus didelphyls
Complete failure of fusion of Mullerian ducts –> double uterus, vagina, cervix