Module 3: Sexual Differentiation Flashcards
Most reproductive organs originate from _____________
Mesoderm
Reproductive system starts to develop very _________ (late/early) in fetal life
early
Vagina/vestibule and penis/clitoris come from the _________
ectoderm
What are the undifferentiated gonads?
_ Primordial Germ cells
- Mesenchymal (interstitial) cells (Theca or Leydig)
- Secrete Steroids
- Coelomic epithelium (Granulosa or Sertoli)
- Sustain GC and foster its maturation and guide its movement
- Gonadal Sex is determined by ______________________
- no hormone is necessary
Sex Chromosome
Sertoli cells = Anti-Mullerian Hormone (AMH)
Leydig cells = Testosterone
Male Chromosome Pair
Granulosa and Theca cells
No Testosterone = Wolffian duct regress
Female Chromosome Pair
What requires hormones?
differentiation of Genital Ducts
Paramesonephric (Mullerian) Ducts
Female
Mesonephric (Wolffian) Duct
Males
What is required for Wolffian ducts to develop?
Testosterone
What causes regression of Mullerian ducts?
AMH
Female:
No AMH = _____________________
Mullerian ducts develop
the precursor of the penis and the clitoris
Genital tubercle
promotes prostate growth, sebaceous gland activity, male pattern baldness, and body, facial and pubic hair growth
dihydrotestosterone (DHT)
Genital tubercle = __________________
Glans Penis
___________ External Genitalia
- Hormones not necessary for differentiation
- Estrogen is required to promote growth to normal size
- Exogenous androgens = masculinization
Females
- Female calf born co-twin to a male calf
- Male gonad develops earlier and secretes Testosterone
- Anastomosis in placental circulation between twins
- Testosterone causes masculinization of female twin
Freemartin Calves
- Female calf born co-twin to a male calf
- Male gonad develops earlier and secretes Testosterone
- Anastomosis in placental circulation between twins
- Testosterone causes masculinization of female twin
Freemartin Calves
- Segmental Aplasia
- “Short Vestivule/Vagina”
- Tuft of hair in vulva
Freemartin Heifers
What is responsible for differentiation of brain?
Estrogen
_______________ binds Estradiol in Females
- Cannot Cross B-B Barrier
Α-FetoProtein
_______________ binds Estradiol in Females
- Cannot Cross B-B Barrier
Α-FetoProtein
Pattern of gonadotropin release
Males:
Constant
Pattern of gonadotropin release:
Females:
Cyclic (presence of Surge Center in hypothalamus)
Converts T into E2
Aromatase
Α-FetoProtein does not bind ____________ in Males
- Can Cross B-B Barrier
Testosterone
