Module 3: Sexual Differentiation

Question 1

Most reproductive organs originate from _____________

Answer 1

Mesoderm

Question 2

Reproductive system starts to develop very _________ (late/early) in fetal life

Answer 2

early

Question 3

Vagina/vestibule and penis/clitoris come from the _________

Answer 3

ectoderm

Question 4

What are the undifferentiated gonads?

Answer 4

_ 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

Question 5

• Gonadal Sex is determined by ______________________
• no hormone is necessary

Answer 5

Sex Chromosome

Question 6

Sertoli cells = Anti-Mullerian Hormone (AMH)
Leydig cells = Testosterone

Answer 6

Male Chromosome Pair

Question 7

Granulosa and Theca cells
No Testosterone = Wolffian duct regress

Answer 7

Female Chromosome Pair

Question 8

What requires hormones?

Answer 8

differentiation of Genital Ducts

Question 9

Paramesonephric (Mullerian) Ducts

Answer 9

Female

Question 10

Mesonephric (Wolffian) Duct

Answer 10

Males

Question 11

What is required for Wolffian ducts to develop?

Answer 11

Testosterone

Question 12

What causes regression of Mullerian ducts?

Answer 12

AMH

Question 13

Female:
No AMH = _____________________

Answer 13

Mullerian ducts develop

Question 14

the precursor of the penis and the clitoris

Answer 14

Genital tubercle

Question 15

promotes prostate growth, sebaceous gland activity, male pattern baldness, and body, facial and pubic hair growth

Answer 15

dihydrotestosterone (DHT)

Question 16

Genital tubercle = __________________

Answer 16

Glans Penis

Question 17

___________ External Genitalia
- Hormones not necessary for differentiation
- Estrogen is required to promote growth to normal size
- Exogenous androgens = masculinization

Answer 17

Females

Question 18

• 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

Answer 18

Freemartin Calves

Question 18

• 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

Answer 18

Freemartin Calves

Question 19

• Segmental Aplasia
• “Short Vestivule/Vagina”
• Tuft of hair in vulva

Answer 19

Freemartin Heifers

Question 20

What is responsible for differentiation of brain?

Answer 20

Estrogen

Question 21

_______________ binds Estradiol in Females
- Cannot Cross B-B Barrier

Answer 21

Α-FetoProtein

Question 21

_______________ binds Estradiol in Females
- Cannot Cross B-B Barrier

Answer 21

Α-FetoProtein

Question 22

Pattern of gonadotropin release
Males:

Answer 22

Constant

Question 23

Pattern of gonadotropin release: Females:

Answer 23

Cyclic (presence of Surge Center in hypothalamus)

Question 24

Converts T into E2

Answer 24

Aromatase

Question 25

Α-FetoProtein does not bind ____________ in Males - Can Cross B-B Barrier

Answer 25

Testosterone