03 - Hormonal Sex (12)

Question 1

(hormonal sex)

1. What determines major hormonal products?
2. does it matter what the chromosomal makeup is?

Answer 1

1. whether it becomes testicle or ovary (important in determining further sexual differentiation)
2. no

Question 2

(hormonal sex)

1. functional testes secrete what three things?

important for what?

Answer 2

1. testosterone, anti-Mullerian hormone (AMH aka mullerian inhibiting substance MIS), and Insulin-factor3

subsequent differentiation as a male during fetal life, and secondary sex characteristics

Question 3

(hormonal sex)

1. what is the main ovarian product?
2. do extrogens play a role in development of the ovary or femal phenotype during fetal life?
3. Estrogen vital for changes seen during and after puberty?

Answer 3

1. estrogen
2. no (because both sexes exposed to marnally produced estrogens during embryonic and fetal life)
3. yes (include physiology of ovarian cycles and secondary sex changes, maintenance of ovary (prevents loss of follicles and transformation toward male (testicular) structures)

Question 4

(Hormonal Sex)

1. Once a testicle is formed the remainder of mammlian sex differentiation is due to what three hormonal products?
2. Castration of a male fetus (prior to testis determination) results in development of a phenotypically female or male?

Answer 4

1. testosterone, MIS, INSL-3
2. female

Question 5

(Androgens)

1. Produced from cholesterol from what cells of the testicle?
2. What is the major androgen produced?
3. What is formed from testosterone by the 5a-reductase enzyme?
4. This enzyme has two known isoforms, which is present in the external genitalia?

Answer 5

1. Leydig cells
2. testosterone
3. dihydrotestosterone (DHT)
4. type II

Question 6

(The 3 stages of testosterone secretion)

1. How many sexually dimorphic peaks of testosterone are there during development?

(The 3 stages)

1. during gestation (10-20 wekks in humans) to do hwat?
2. Perinatal - sets what?
3. Continues from puberty - does what?

Answer 6

1. 3 (timing depends on species)
2. masculinize the female genitalia
3. brain sex and other sexual dimorphisms (fetal period of ruminants, at birth in pigs, post-natal in humans from 6 months to first few years)
4. gives secondary sex characteristics, spermatogenesis

Question 7

(Androgens)

(Mullerian inhibiting substance (MIA; aka anti-Mullerian hormone ASH)

1. glycoprotein produced by what in males?
2. Causes regression of what in male fetuses?
3. Expression of MIS is male specific until after birth
4. Are high levels found in the serum of male fetuses? in females?

Answer 7

1. Sertoli
2. Mullerian ducts
3. yes; no

Question 8

(Phenotypic Sex)

(Sexual Differentiation of the Reproductive Tracts)

just read page 14 and 15

Question 9

(Androgens)

1. Both testosterone (T) and dihydrotestosterone (DHT) bind the same receptor to have their effects… what is that receptor?

2 T-AR signals what in male embryo?

3. DHT-AR signals what in male embryo? causes what else?
4. Different effects of hormones binding may have something to do with different binding affinity.

which has greater binding affininty?

may also have to do with receptor funciton…

which activates more genes easily?

Answer 9

1. androgen receptor
2. differentiation of the Wolffian duct (also later regulates hypothalamo-pituitary axis for LH secretion and has a vital role in spermatogenesis
3. development of external genitalia and prostrate; elongation and ventral closure of the penile anlagen to move th eurethral orifice from the perinuem to the tip of the penis

(also involved in peubertal changes eg hair pattern, male pattern baldness and maturation of external genitalia, and possibly role in male specific behavior)

DHT has 10x greater that T

DHT-AR

Question 10

(Mullerian inhibitng substance - MIS aka anti-Mullerian hormone AMH)

1. Causes regression of what in male fetuses?
2. Does it act locally by diffustion…. or as a secreted hormone?
3. Which happens earlier… regression of Mullerian duct in males or Olffian duct in females?
4. Mullerian ducts of developing embryos are only sensitive to MIS for a short period… when is it?

Answer 10

1. the Mullerian ducts
2. acts locally
3. regression of mullerian duct in males
4. shorly after gonadal sex differentiation

Question 11

(Differentiation of the female reproductive tract)

1. in the absence of testosterone and MIS what happens to wolffian and mullerian ducts?
2. The oviducts (Fallopian tubes) develop from what?
3. When do the fimbria that will pick up the oocytes following ovulation develop relative to development of the oviduct?

Answer 11

1. wolffian ducts regress, mullerian ducts develop
2. the cranial portion of the Mullerian duct (adjacent the ovary)
3. after (in species with short gestation this may not occur until after birth)

Question 12

(During uterine and cervical development there is fusion of the left and right Mullerian ducts to varying degrees depending on species)

(say which animal)

1. duplex uterus with totally separate horns and 2 cervixes
2. bicornuate uterus with totally seprate uterine horns and 2 cervixes
3. bipartite uterus with a larger uterine body
4. simplex uterus, where the oviducts enter directly in the uterine body

Answer 12

1. rabbit
2. pigs
3. ruminants
4. primates