Spermatogenesis

Question 1

Why are the testes outside the body?

Answer 1

Overheating of the testes cause a reduced sperm count

Question 2

Where are Sertoli cells found?

Answer 2

On the basement membrane

Question 3

What is the normal volume of the testes?

Answer 3

15-25ml

Question 4

What are the walls of the seminiferous tubules made up of?

Answer 4

Tall columnar epithelial Sertoli cells

Question 5

What forms the adluminal compartment?

Answer 5

Tight junctions between the tall columnar epithelial Sertoli cells

Question 6

What are the spaces between the seminiferous tubules filled with?

Answer 6

Blood and lymphatic vessels, leydig cells and interstitial fluid

Question 7

What process forms a primary spermatocyte from spermatogonia?

Answer 7

Mitosis

Question 8

What process forms a secondary spermatocyte from a primary spermatocyte?

Answer 8

Meiosis I

Question 9

What process forms a spermatid from a secondary spermatocyte?

Answer 9

Meiosis II

Question 10

Are spermatogonia haploid or diploid?

Answer 10

Diploid

Question 11

Are primary spermatocytes haploid or diploid?

Answer 11

Diploid

Question 12

Are secondary spermatocytes haploid or diploid?

Answer 12

Haploid

Question 13

How often does spermatogenesis start?

Answer 13

Every 16 days

Question 14

How long does the entire spermatogenesis process take?

Answer 14

74 days

Question 15

What are the three steps in spermatogenesis?

Answer 15

Mitotic proliferation of spermatogonia, meiosis and development of spermatocytes and then spermatogenesis, elongation, loss of cytoplasm and movement of cellular contents

Question 16

How do the spermatids stay connected to one another?

Answer 16

Cytoplasmic bridges between cells

Question 17

Why do the spermatids stay connected to each other?

Answer 17

Allows synchronous development

Question 18

What is the primary steroidal function of the Leydig cells?

Answer 18

Contain LH receptors and convert cholesterol into androgens

Question 19

What are the intratesticular testosterone levels like when compared to plasma?

Answer 19

Double

Question 20

What type of receptors do Sertoli cells contain?

Answer 20

FSH

Question 21

What is the steroidal function of Sertoli cells?

Answer 21

Convert androgens to oestrogen

Question 22

What happens if you take anabolic steroids (testosterone)?

Answer 22

Reduce the FSH from the pituitary leading to testicular atrophy because of diminishing Sertoli cell production

Question 23

What part of the nervous system controls erection?

Answer 23

Parasympathetic

Question 24

What part of the nervous system controls movement of sperm into the penile urethra?

Answer 24

Sympathetic

Question 25

What part of the nervous system controls expulsion of glandular secretions and eviction of the penile urethra?

Answer 25

Somatic

Question 26

What part of the somatic nervous system is involved in ejaculation?

Answer 26

Perineal branch of the pudendal nerve from nerve roots S2-S4

Question 27

On average, how many sperm are produced every day?

Answer 27

300 million

Question 28

How many sperm are in an average ejaculate?

Answer 28

120 million

Question 29

What is the volume of normal ejaculate?

Answer 29

1.5-6 ml

Question 30

How much sperm is lost before reaching the ampulla of the uterine tube?

Answer 30

99.9%

Question 31

Where does the seminal fluid contain secretions from?

Answer 31

Seminal vesicles Prostate Bulbourethral glands Epididymal fluid

Question 32

What does the bulbourethral gland produce?

Answer 32

Clear, viscous mucus high in salt

Question 33

What is the purpose of the bulbourethral gland secretions?

Answer 33

Lubricates the urethra for sperm to pass through and neutralising traces of acidic urine

Question 34

How much of the ejaculate is made up of seminal fluid?

Answer 34

50-70%

Question 35

What does the seminal fluid contain?

Answer 35

Proteins

Question 36

Why does the seminal fluid contain a high concentration of fructose?

Answer 36

Energy source

Question 37

Why does the seminal fluid have a high pH?

Answer 37

Protects against the acidic environment of the vagina

Question 38

How much of the seminal fluid is made up of prostatic fluid?

Answer 38

30%

Question 39

What enzymes are in the prostatic fluid?

Answer 39

Proteolic enzymes, prostatic acid phosphatase and prostate-specific antigens

Question 40

Why does the prostatic fluid contain such a high concentration of zinc?

Answer 40

Antibacterial

Question 41

What is oligospermia?

Answer 41

<15 million/ml sperm in semen

Question 42

What is aspermia?

Answer 42

Complete lack of sperm in semen

Question 43

What is the acrosome full of?

Answer 43

Enzymes

Question 44

Why is the acrosome full of enzymes?

Answer 44

Break down the outer layers of the oocyte

Question 45

What is the axoneme?

Answer 45

9 pairs of fibres that run longitudinally down the sperm tail

Question 46

What does the axoneme allow?

Answer 46

Movement of the sperm tail