Reproductive

Question 1

TDF (testis determining factor) will…

Answer 1

cause undifferentiated gonad to become testes (absence essentially creates ovaries)

Question 2

Testes secrete:

Answer 2

Mullerian-inhibitory factor (regress ducts), testosterone (growth of seminal vesicles, vas deferens), DHT (external genitalia - phallus and prostate)

Sertoli responsible for MIF, Leydig for testosterone

Question 3

What is androgen insensitivity syndrome?

Answer 3

Defective androgen receptors

- no response to testosterone; no external genitalia; degeneration of Wolffian ducts

Question 4

What does a mutation in 5-alpha-reductase cause?

Answer 4

(Can’t go from testosterone to DHT):

• Wolffian ducts okay: epididymis, vas deferens, seminal vesicle, ejactulatory duct
• DHT absence: hypospadias, “female” external genitalia, lack of prostate glands

** Male pseudohermaphroditism (ambiguous genitalia)

Question 5

Pituitary gonadotropins:

Gonadal hormones:

Answer 5

• LH, FSH (anterior pituitary)
• estrogens, progesterone, testosterone, DHT (feedback mostly negative and on the pituitary)

Hypothalamus produces gonadotropin-releasing hormone
There’s also inhibin :)

Question 6

What converts testosterone to DHT?

Answer 6

5-alpha-reductase

DHT 50x more potent

Question 7

What converts testosterone to estradiol?

Answer 7

aromatase

In granulosa cells and peripheral (esp. adipose) tissue

Question 8

Females get most androgens from:

Males get most estrogens from:

Answer 8

adrenal

peripheral conversion of androgens

Question 9

Effects of estrogen:

Answer 9

• Uterus: generalized trophic effect; proliferation of endometrium
• Cervix: increase in quantitiy/decrease in viscosity of mucus
• Vagina: thickening of epithelium
• Breasts: proliferation of ducts
• Bone: linear growth, epiphyseal closure

Estrogens: estradiol-17beta, estrone, estriol

Question 10

Action of progesterone:

Answer 10

Pro-gestational changes

• proliferative to secretory endometrium
• inhibit SM contractility
• natriuresis with increased respiration
• increase viscosity of cervical mucus
• acinar and lobular development in breasts

Question 11

Sex Hormone Binding Globulin:

Answer 11

• inversely related to weight
• inversely related to insulin
• decreased by androgens

Question 12

Pre-puberty is characterized by inhibitory pulses of…

Answer 12

GnRH (very sensitive negative feedback)

Question 13

Testosterone inhibits LH release by…

Answer 13

Inhibiting GnRH release and by decreasing sensitivity to GnRH (chronic)

Question 14

What does inhibin do?

Answer 14

Inhibits FSH release (pituitary)

- synthesized in response to androgens

Question 15

What does activin do?

Answer 15

Stimulates secretion of FSH

released by Sertoli cells

Question 16

Most testosterone in the blood isn’t free. It’s bound to:

Answer 16

SHBG and albumin

Question 17

5-alpha-reductase blockers can do what in older men?

Answer 17

Reduce prostate hyperplasia

Question 18

What do LH and FSH do?

Answer 18

LH: Leydig cells; stimulate cholesterol desmolase to start making testosterone; acts via cAMP

FSH: Sertoli cells; make androgen-binding protein to stimulate spermatogenesis
- increased sensitivity to FSH in these cells at puberty

Question 19

1 spermatogonium (2n) =

Answer 19

512 spermatozoa (1n)

no idea how relevant this is