Reproductive Physiology

Question 1

The SRY on the Y chromosome of a genetic male is responsible for development of what?

Answer 1

testes

Question 2

Absence of the SRY will result in what?

Answer 2

ovaries

Question 3

What are the male internal genitalia?

Answer 3

epididymis, vas deferens, seminal vesicles

Question 4

What are the male external genitalia?

Answer 4

prostate, penis, scrotum

Question 5

What are the female internal genitalia?

Answer 5

fallopian tubes, uterus, upper 1/3 of vagina

Question 6

What are the female external genitalia?

Answer 6

labia majora, labia minora, clitorus, lower 2/3 of vagina

Question 7

What does the Wolffian duct develop into?

Answer 7

male internal genitalia

Question 8

What does the Mullerian duct develop into?

Answer 8

female internal genitalia

Question 9

What is important for the development of male internal structures?

Answer 9

• testosterone for development of Wolffian duct

- Anti-Mullerian hormone to regress Mullerian duct

Question 10

In the absence of testosterone and Anti-Mullerian hormone, what occurs?

Answer 10

Wolffian duct regress, mullerian duct develops into female internal structures

Question 11

If a genetic male has no testosterone, but has AMH, what occurs?

Answer 11

Wolffian duct doesn’t develop, Mullerian duct regresses, so no internal structures of either sex

Question 12

If a genetic male has testosterone, but no AMH, what occurs?

Answer 12

Wolffian duct develops so male internal genitalia develops; Mullerian duct doesn’t regress so female internal structures also develop

Question 13

At what point are Wolffian and Mullerian ducts present in the fetus?

Answer 13

7 weeks

Question 14

At what points do external genitalis develop?

Answer 14

9-12 weeks

Question 15

Development of male external genitalia requires what hormone?

Answer 15

dihydrotestosterone

Question 16

What converts testosterone to dihydrotestosterone?

Answer 16

5-alpha reductase

Question 17

What inhibits 5-alpha reductase? what is this used for?

Answer 17

finesteride; used in benign prostatic hyperplasia

Question 18

What does absence of 5-alpha reductase result in?

Answer 18

won’t convert testosterone to dihydrotestosterone, so male external genitalia won’t develop; will have female external genitalia

Question 19

• rudimentary or absent gonads
• female internal and external genitalia
• short stature
• lack of sexual maturity adn infertility
• amenorrhea
• coarctation of aorta
• horse shoe kidney
• short 4th metacarpals
• 45X0

Answer 19

Turner’s Syndrome

Question 20

• testes with poorly developed seminiferous tubules
• male internal and external genitalia are present
• testes secret low amount of testosterone and AMH
• high plasma estradiol causing gynaecomastia
• infertility

Answer 20

Klinefelter’s Syndrome (47XXY)

Question 21

abnormal sexual development during fetal stage

Answer 21

aberrant sexual differentiation

Question 22

abnormal secretion of hormones during female stage

Answer 22

hormonal abnormalities

Question 23

• 46XX with ovaries/female internal genitalia

- ambigous external genitalia

Answer 23

Female pseudohermaphroditism

Question 24

• 46XY
• may or may not have male/female internal genitalia
• has female external genitalia
• defect: failure of testes to secrete testosterone or testosterone and AMH

Answer 24

Male pseudohermaphroditism

Question 25

- testosterone is not converted to dihydrotestosterone so male external genitalia cannot be developed - is born with female external genitalia - has male internal genitalia - 46XY

Answer 25

5-alpha reductase deficiency syndrome

Question 26

- has undescended testes which secrete testosterone - testosterone receptors are defective, so testosterone can't bind the receptors, so can't differentiate into wolffian duct for internal structures; external structures can't develop since dihydrotestosterone can't bind with receptors - AMH is present, so Mullerian duct regresses and female internal genitalia doesn't form - has female external genitalia

Answer 26

Testicular Feminization/androgen Insensitivity Syndrome

Question 27

Where are leydig cells found? What do they produce?

Answer 27

- found outside the seminiferous tubules | - produce testosterone after LH binds to it

Question 28

Where are sertoli cells found? What acts on them?

Answer 28

- found within the seminiferous tubules | - FSH acts on them for spermatogenesis

Question 29

damaged hypothalamus causing decreased GnRH

Answer 29

tertiary hypogonadism

Question 30

damaged Ant. Pit causing no FSH/LH to be released

Answer 30

secondary hypogonadism

Question 31

damaged testis which cannot make testosterone

Answer 31

primary hypogonadism

Question 32

What does LH stimulate?

Answer 32

LH stimulates Leydig cells to secrete testosterone

Question 33

What does FSH stimulate?

Answer 33

FSH stimulates Sertoli cells to secrete inhibin

Question 34

How is LH regulated?

Answer 34

by negative feedback of testosterone

Question 35

What does inhibin do?

Answer 35

it has negative feedback to the anterior pituitary to decrease FSH activity

Question 36

What id the function of Sertoli and Leydig cells in cryptorchidism?

Answer 36

sertoli and leydig cell maturation is impaired

Question 37

In adults with bilateral undescended testes...: - there is decreased production of Inhibin by Sertoli cells - decreased testosterone secretion by Leydig cells - What do these events cause?

Answer 37

- FSH secretion is elevated due to decreased production of Inhibin since inhibin normally inhibits FSH - Testosterone secretion is low which results in elevated levels of LH

Question 38

Which phase of the menstrual cycle is fixed?

Answer 38

luteal

Question 39

What is the major estrogen secreted by ovaries?

Answer 39

Estradiol?

Question 40

What is the major estrogen secreted by placenta?

Answer 40

Estriol