Male Reproductive Physiology

Question 1

Why do the testes sit within the scrotum?

Answer 1

Testicular temperature has to be below body temperature to facilitate sperm production

Question 2

What is the site of sperm production?

Answer 2

Testes

Question 3

Where is sperm stored after it is produced in the testes?

Answer 3

Epididymis

Question 4

What connects the epididymis to the seminal vesicles?

Answer 4

Vas deferens

Question 5

What is 1?

Answer 5

Epididymis: stores sperm, site of sperm maturation

Question 6

What is 2?

Answer 6

Prostate gland

Question 7

What is 3?

Answer 7

Penis

Question 8

What is 4?

Answer 8

Penile urethra

Question 9

What is 5?

Answer 9

Testis

Question 10

What is 6?

Answer 10

Scrotum

Question 11

What is the site of sperm production?

Answer 11

Seminiferous tubules

Question 12

What types of cells are found within the seminiferous tubules?

Answer 12

• Germ cells
• Sertoli/sustentacular cells
• Interstitial (Leydig) cells

Question 13

What do germ cells produce?

Answer 13

Sperm

Question 14

What do Sertoli cells produce?

Answer 14

• Support sperm producing cell
• Produce inhibin

Question 15

What do interstitial (Leydig) cells produce?

Answer 15

Testosterone

Question 16

What is a?

Answer 16

Interstitial (Leydig) cell

Question 17

What is b?

Answer 17

Basement membrane

Question 18

What is c?

Answer 18

Sertoli cells

Question 19

What is d?

Answer 19

Spermatogonia

Question 20

What is e?

Answer 20

Primary and secondary spermatocytes

Question 21

What is f?

Answer 21

Spermatids

Question 22

What is g?

Answer 22

Sperm cells

Question 23

What are the main functions of the testes?

Answer 23

• Sperm production
• Testosterone production

Question 24

What hormones are important for testicular function? Where are they released from?

Answer 24

• GnRH: Gonadotropin-releasing hormone (hypothalamus)
• Gonadotropins: FSH, LH (anterior pituitary)
• Testosterone (testicles)

Question 25

What effect does inhibin have on the anterior pituitary in males?

Answer 25

Inhibits anterior pituitary

Question 26

What effect does testosterone have on the anterior pituitary and hypothalamus in males?

Answer 26

Inhibition

Question 27

Draw the positive and negative feedback loops for the hormones that act on the hypothalamic-pituitary-testicular axis

Answer 27

Question 28

What is spermatogenesis?

Answer 28

Sperm production from primordial germ cells

Question 29

How long is the average cycle of spermatogenesis?

Answer 29

64 days

Question 30

What are the 2 phases of spermatogenesis?

Answer 30

1. Spermatocytogenesis: clonal expansion and maturation through the mitotic and meiotic process 2. Spermiogenesis: Differentiation into mature sperm cells

Question 31

When does spermatogenesis start, and how long does it last?

Answer 31

* Starts at puberty * Continues lifelong

Question 32

What effect do pituitary hormones have on sperm production?

Answer 32

Positive feedback loop

Question 33

What effect do testes hormones have on sperm production?

Answer 33

Negative feedback loop

Question 34

Describe the process of spermatogenesis

Answer 34

Question 35

Describe the chromosomal division during spermatogenesis

Answer 35

* 1 mitotic division (Spermatogonium → 1ry spermatocyte) - duplication (2n) * 1st meiotic division (1ry spermatocyte → 2ry spermatocyte) - 2 haploids (1n) * 2nd meotic division (2ry spermatocyte → spermatid)- 2 cells with (1n)

Question 36

What is spermiogenesis?

Answer 36

Maturation of spermatids into functional sperm cells

Question 37

What factors affect spermatogenesis and subsequent infertility?

Answer 37

* Medical * Lifestyle * Combination of both

Question 38

What are the medical factors that can affect spermatogenesis?

Answer 38

* **Pretesticular:** hormone control problem * Functional: excess weight gain/loss * Intracranial tumours/cyst/bleed * Prolactinoma * Meications: opiates/external testosterone/steroids * Genetic: Kallmann's syndrome * **Testicular**: problem at the site of production * Surgery: orchidectomy, orchidopexy * STI * Mumps orchitis * Testicular trauma/tortion * RTx, CTx * Genetic: Kleinfelter's (46XXY), Y-chromosome microdeletion

Question 39

What lifestyle factors can affect spermatogenesis?

Answer 39

* Smoking * Obesity * Occupational/chemical exposures

Question 40

What improvements in lifestyle factors can help improve spermatogenesis?

Answer 40

* Normal BMI, healthy diet and exercise * Smoking cessation * Limited alcohol consumption * Occupational exposure adjustments * Optimise underlying medical conditions * Cease medications * Reduce STI risk * Fertility prevention: sperm freezing prior to surgery/cancer treatment

Question 41

What are important things to ask that relate to male fertility during history taking?

Answer 41