Lect 9 - Male Reproduction

Question 1

What type of cells, along with spermatogonia, line the lumen of the seminiferous tubules?

Answer 1

Sertoli cells

Question 2

Where do Leydig cells lie in relation to the seminiferous tubules?

Answer 2

in the interstitium

Question 3

Which cells are responsible for the blood-testis barrier?

Answer 3

Sertoli cells

Question 4

Where is LH released from? FSH?

Answer 4

both from anterior pituitary

Question 5

LH binds receptors on which cells?

Answer 5

Leydig cells

Question 6

What happens after LH binds receptors in the testes?

Answer 6

increase in cAMP, increase in PKA, increased transcription and production of testosterone

Question 7

What second messenger is involved in FSH receptor binding?

Answer 7

cAMP

Question 8

What are four molecules/types of molecules that are increased with FSH receptor binding?

Answer 8

1) inhibin
2) aromatase
3) androgen binding protein
4) growth factors

Question 9

What is the purpose of inhibin?

Answer 9

inhibit FSH

Question 10

What is the general interaction between Leydig and Sertoli cells?

Answer 10

Leydig cells produce testosterone, travels to Sertoli cells which converts it to estradiol; growth factors then migrate from Sertoli cells to Leydig cells

Question 11

What are some regulators of the release of GnRH?

Answer 11

• sleep/wake cycle
• negative feedback
• stress
• hormones

Question 12

What structure does GnRH act on?

Answer 12

anterior pituitary

Question 13

How and how often is GnRH released from the hypothalamus?

Answer 13

pulsatile release, every 1-3 hours

Question 14

What type of cells release GnRH and where are these cells?

Answer 14

gonadotrophs in the hypothalamus

Question 15

What is the second messenger present in gonadotroph cells which causes release of LH/FSH?

Answer 15

IP3 and DAG–>Ca increase

Question 16

Where does testosterone exert its negative feedback on? Where does inhibin exert its negative feedback?

Answer 16

Testosterone inhibits the hypothalamus and the anterior pituitary. Inhibin inhibits the anterior pituitary.

Question 17

How much of testosterone is bound in plasma?

Answer 17

97%

Question 18

What are the two molecules that testosterone is bound to in the plasma?

Answer 18

1) sex-hormone binding globulin

2) albumin

Question 19

In what state does testosterone exert a physiological action?

Answer 19

free testosterone unbound to plasma protein

Question 20

What type of receptors does testosterone bind to?

Answer 20

nuclear receptors

Question 21

beta-hCG is analogous to which hormone?

Answer 21

luteinizing hormone

Question 22

There are three times that testosterone will spike in males during a lifetime, when are they?

Answer 22

1) in utero - sex determination
2) right after birth - ? reason
3) during puberty - secondary sex characteristics

Question 23

The ejaculate volume is stored in three areas of the male reproductive system…what are these areas?

Answer 23

1) epididymis/vas deferens
2) seminal vesicles
3) prostate

Question 24

Which part of the male reproductive system adds the most volume to the ejaculate?

Answer 24

seminal vesicles

Question 25

What neural activity is responsible for an erection?

Answer 25

Increase in parasympathetic activity

Question 26

What second messenger is increased which relaxes smooth muscle to allow for an erection?

Answer 26

cGMP

Question 27

Which vasoactive substances work to vasodilate in erectile tissue?

Answer 27

nitric oxide and acetylcholine

Question 28

What are some common causes of ED?

Answer 28

1) diabetes mellitus
2) drugs
3) stress

Question 29

Which enzyme does Levitra, Cialis, and Viagra all inhibit?

Answer 29

Phosphodiesterase 5 (PDE5)

Question 30

What is one complication of priapism?

Answer 30

necrosis of tissue

Question 31

What is Fröhlich’s syndrome?

Answer 31

hypothalamic tumor leading to obesity and depressed release of gonadotropin

Question 32

What is another name for Fröhlich’s syndrome?

Answer 32

adiposogenital dystrophy