Endo: Male reproduction L9

Question 1

describe GnRH
size
where is it produced?

Answer 1

• 10aa peptide

- mainly ROSTRAL (pre-optic area) , in primates some caudal (arcuate nuclei)

Question 2

LH and FSH are what kinds of substance?

Answer 2

• glycoproteins

Question 3

what is the role of LH in men? femal?

Answer 3

• testosterone production MEN

- ovulation, maintains corpus luteum

Question 4

what is the role of FSH in men? femal?

Answer 4

• spermatogenesis MEN

- follicular development FEMAL

Question 5

give 3 examples of steroidal reproductive hormones?

Answer 5

• testosterone
• oestrogen
• progesterone

Question 6

inhibin is what type of hormone?

what is its structure?

Answer 6

• peptide
• dimer of 2 subunits
• selective INHIBITION of FSH a secretion

Question 7

each lobule of the testis contains how many seminiferous tubules?

Answer 7

2-3

Question 8

what are the peripheral effects of testosterone?

Answer 8

• mainly via coversion to 5a-dihydrotestosterone by 5a-reductase

Question 9

what is the function of the blood testis barrier?

Answer 9

• protect sperm from blood borne substances

- prevents antigenic substances entering circulation (can cause infertility)

Question 10

where does spermatogenesis occur?

Answer 10

seminiferous tubules

Question 11

where is sperm STORED

Answer 11

Vas deferens and epididymis

Question 12

what does FSH act on

Answer 12

Sertoli cells

• stimulates prod of ANDROGEN BINDING PROTEINS and inhibin
• initiation of SPERMATOGENESIS
• differentiation of spermatids–> spermatozoa

Question 13

what does LH act on

Answer 13

• stimulates production of TESTOSTERONE

Question 14

what is the cause of infertility (50%)/

Answer 14

• abnormality of male reproduction

Question 15

spermatogenesis defects account for how much of failed conception?

Answer 15

• 10%
• low gonadotrophin secretion
• testis malfunction
  (cryptorchidism- undescended testes,
  disease- mumps, genetic- Klinefelter’s syndrome, physical damage- to blood testis barrier)