Physiology of Reproduction

Question 1

What determines genetic sex?

Answer 1

Chromosomes. XX or XY

Question 2

What determines gonadal sex?

Answer 2

Testes or Ovaries

Question 3

What determines genital sex?

Answer 3

External genitalia which is influenced by hormones

Question 4

What is SRY?

Answer 4

Sex determining region of the Y chromosome

Question 5

What is ovary development dependent upon?

Answer 5

The presence of TWO X chromosomes

Question 6

What happens with the loss of a single X chromosome as in Turner’s syndrome?

Answer 6

Loss of one X chromosome results in ovarian dysgenesis but not loss of female ducts or genitalia

Question 7

What occurs in meiosis I?

Answer 7

Chromosomes duplicate and exchange genetic material. Results in haploid numbers of duplicated chromosomes

Question 8

What occurs in meiosis II?

Answer 8

Daughter cells have haploid (1N) chromosomes with the segregation of sex chromosomes providing a mechanism of sexual dimorphism.

Question 9

What does sperm production require?

Answer 9

Reduced temperature

Question 10

Is gonadal sex hormone dependent?

Answer 10

NO. It cannot be as the gonads make the hormones.

Question 11

How is the decision for the progression to female genital structures made?

Answer 11

It occurs when there is no androgens present. Presence of androgens will influence male structure development.

Question 12

What develops into seminiferous tubules, spermatogonia, sertoli cells, leydig cells?

Answer 12

Medulla

Question 13

What develops into secondary sex cords, oogonia, theca cells, granulosa cells?

Answer 13

Cortex

Question 14

What is the function of testosterone in regards to the ductal structures?

Answer 14

Keeps the Wolffian ducts

Question 15

What is the function of AMH in regards to the ductal structures?

Answer 15

Degrades the Mullerian ducts

Question 16

What happens if neither AMH nor testosterone are present?

Answer 16

The Mullerian ducts will remain and the Wolffian ducts will be lost resolution in a female.

Question 17

What is the function of TDF?

Answer 17

It directs the development of the testes

Question 18

What is the function of DHT?

Answer 18

It is more potent of an androgen than testosterone and it causes male genitalia development via androgen receptors.

Question 19

What is the function of 5alpha-reductase?

Answer 19

Converts testosterone to DHT

Question 20

What is the chromosome state of Turner’s Syndrome?

Answer 20

XO

Question 21

What are the gonads/ducts/genitals found in Turner’s syndrome?

Answer 21

No gonads (only streak)
Mullerian
NO Wolffian
External female genitals

Question 22

What is male pseudohermaphroditism?

Answer 22

Testes are present with external female genitals

Question 23

What is female pseudohermaphroditism?

Answer 23

Ovaries are present with external male genitals

Question 24

What causes male pseudohermaphroditism?

Answer 24

Androgen resistance

Question 25

What causes female pseudohermaphroditism?

Answer 25

Excess androgens

Question 26

What is the chromosome state found in androgen resistance?

Answer 26

XY

Question 27

What are the gonads/ducts/genitals found in androgen resistance (AKA testicular feminization)?

Answer 27

Testes NO Mullerian NO Wolffian External female genitals

Question 28

What is the chromosome state found in 5alpha-hydroxylase deficiency?

Answer 28

XY

Question 29

What are the gonads/ducts/genitals found in 5alpha-hydroxylase deficiency?

Answer 29

Testes NO Mullerian Wolffian External can be male/female or both

Question 30

What is the chromosome state found in Klinefelter's Syndrome?

Answer 30

XXY

Question 31

What are the gonads/ducts/genitals found in Klinefelter's Syndrome?

Answer 31

Dysgenic Testes NO Mullerian Wolffian External male genitals

Question 32

What is the function of aromatase?

Answer 32

Converts testosterone into estrogen

Question 33

What is testosterone found as in the plasma?

Answer 33

45% is bound to SHBG (sex hormone binding globulin) 55% bound to albumin and corticosteroid-binding globulin (CBG) 2% is free – biologically active and may diffuse into cells

Question 34

What does testosterone affect directly?

Answer 34

Differentiation of the epididymus and vas deferens Larynx Skeleton Increases abdominal visceral fat Increases muscle mass Increases RBCs

Question 35

What does testosterone affect indirectly via E2/DHT?

Answer 35

Sperm production Beard growth Penis/scrotum development Male pattern baldness

Question 36

What are some treatments for prostate cancer and how are they effective?

Answer 36

5alpha-reductase inhibitors as prostate tumors are often DHT dependent