Lecture 11: Sex Determination and Differentiation

Question 1

Bipotential gonad

Answer 1

tissue has two potential pathways of development (testis or ovary)

Question 2

Müllerian duct

Answer 2

develops into female reproductive tract

Question 3

Wolffian duct

Answer 3

develops into male reproductive tract

Question 4

5 a - reductase and SRY

Answer 4

enzyme that converts T to DHT. Only happens in a genotype that contains a functional SRY.

Question 5

46, XX

Answer 5

normal human female

Question 6

46, XY

Answer 6

normal human male

Question 7

45, XO

Answer 7

Turner Syndrome - ovary develops, broad spectrum of phenotypes from spontaneous abortion (98% of pregnancies) to short stature, ovarian failure and infertility. Most require therapy to develop secondary sex characteristics.

Question 8

47, XXY

Answer 8

Klinefelter Syndome - testis develops, decreased testicular hormonal function known as hypogonadism, low testosterone production, unable to make sperm, enlarged breasts/sparse facial hair/small testes

Question 9

Y chromosome – SRY, AZF

Answer 9

Sex Determining Region on the Y Chromosome (SRY) sits on the short arm of the Y chromosome and determines male appearance.

Question 10

AMH

Answer 10

Anti Mullerian Hormone, expressed by sertoli cells and leads to degeneration of the Mullerian duct (no oviduct, uterus, upper part of vagina). Only expressed in men with functional SRY.

Question 11

DHT and SRY

Answer 11

converted from T by enzyme 5-a reductase. Again, only happens in man with functional SRY region.

Question 12

Endocrine-disrupting compounds

Answer 12

chemicals in the environment that can mimic (agonistic) or obstruct (antagonistic) hormone function. Can target estrogens, androgens, or any other hormone system. Can affect sex determination.