Male reproduction physiology

Question 1

The bulbourethral gland contributes how much of the seminal fluid?

Answer 1

5%

Question 2

The prostate gland contributes how much of the seminal fluid?

Answer 2

30%

Question 3

The Seminal vesicle contributes how much of the seminal fluid?

Answer 3

60%

Question 4

How many sperm per ml are there?

Answer 4

20-200million sperm/ml

Question 5

How much in ml of semen is there usually in a single ejaculation?

Answer 5

2-5ml

Question 6

What is involved in the male reproduction jigsaw?

Answer 6

1) Hormones
2) Testis
3) Sperm production
4) Sperm travel pathway

Question 7

Where is GnRH (Gonadotrophin releasing hormone) released?

Answer 7

Hypothalamus

Question 8

Where are gonadotrophin released?

Answer 8

FSH and LH are released from the anterior pituitary

Question 9

Where is testosterone produced?

Answer 9

The leydig cells of the testis

Question 10

What produces inhibin?

Answer 10

The Sertoli cells

Question 11

What produces sperm?

Answer 11

The germ cells (Sertoli cells)

Question 12

What makes the leydig cells different from the adrenal cortex allowing testosterone production?

Answer 12

They do not contain 21B-hydroxylase or 11B-hydroxylase in contrast to the adrenal cortex.

Therefore, they do not synthesis glucocorticoids or mineralocorticoids

Question 13

What is the role of LH in a man?

Answer 13

In parallel to the action on the adrenal cortex, LH increases testosterone production by stimulating cholesterol desmolase.

Question 14

Which enzyme does LH stimulate allowing an increase in testosterone production?

Answer 14

Cholesterol desmolase within Leydig cells of the testis

Question 15

What is the action of the prostate in hormone production?

Answer 15

The prostate contains 5alpha-redutase which converts testosterone to the more active, dihydrotestosterone.

Question 16

What is the role of FSH in men?

Answer 16

Stimulates the Sertoli cells (spermatogenia) of the Seminiferous tubules to produce sperm, spermatogenesis

Question 17

How does sperm travel from the testis to the urethra?

Answer 17

Throughout the vas deferens

Question 18

where is semen produced?

Answer 18

In the Seminal vesicles and prostate

Question 19

What has to occur to allow a spermatogonium to become a mature sperm cell?

Answer 19

1) Two rounds of meiosis to produce spermatids, then:

2) Spermatogenesis

Question 20

How many sperm are produced each day?

Answer 20

30 million

Question 21

How long does it take to produce sperm?

Answer 21

60-75 days

Question 22

How long does it take to transport sperm to the epididymis?

Answer 22

10-14 days

Question 23

What can affect spermatogenesis?

Answer 23

1) Hormonal control (Genetic, tumours, medication, functional)
2) Problem at the site of production (Genetic, cancer treatment induced, surgical, trauma, infections)

Question 24

What is the negative feedback control of testosterone?

Answer 24

Inhibits LH release by:

1) Inhibiting the release of GnRH form the hypothalamus
2) Inhibiting the release of LH form the anterior pituitary

Question 25

What is the negative feedback control of inhibin?

Answer 25

Inhibits the release of FSH from the anterior pituitary

Question 26

Actions of testosterone in a man?

Answer 26

> Differentiation of the epididymis, vas deferens and seminal vesicles 
> Growth spurt in puberty 
> Epiphyseal closure 
> Libido
> Spermatogenesis in Sertoli cells 
> Deepening of voice 
> Increased muscle mass 
> Growth of penis and seminal vesicles 
> Negative feedback on the anterior pituitary

Question 27

Actions of dihydrotestosterone in a man?

Answer 27

> Differentiation of penis, scrotum and prostate
> Male hair pattern
> Male pattern baldness
> Sebaceous gland activity 
> Growth of the prostate