Sperm - Origins and Role

Question 1

What is the acrosome and what is its function

Answer 1

Cap on head of sperm that contains enzymes to allow it to digest its way into the oocyte

Question 2

In which structure are spermatozoa made?

Answer 2

Seminiferous tubules

Question 3

In which structure do spermatozoa mature?

Answer 3

Epididymis

Question 4

What cells line seminiferous tubules and what is their function?

Answer 4

Sertoli cells - support and nourish spermatozoa

Question 5

What is the female equivalent of Sertoli cells?

Answer 5

Granulosa cells

Question 6

Where cells are found on the outside of seminiferous tubules?

Answer 6

Leydig cells

Question 7

What is the function of Myoid cells?

Answer 7

Maintain blood-testis barrier and prevent antibodies recognising sperm

Question 8

Rising levels of what during puberty re-starts mitosis of prospermatogonia?

Answer 8

Androgens driven by release of GnRH

Question 9

What do spermatogonial stem cells initially differentiate into?

Answer 9

Spermatogonium type A1

Question 10

how many type A1 spermatogonium clones can one spermatogonial stem cell produce?

Answer 10

16

Question 11

How many mitotic cell divisions does type A1 spermatogonia undergo to form a resting primary spermatocyte

Answer 11

5 synchronised: Type A1 > A2 > A3 > A4 >intermediate spermatogonium > type B. Followed by a final mitosis to form
resting primary spermatocytes.

Question 12

What is formed at the end of meiosis 1?

Answer 12

Secondary spermatocytes

Question 13

What is formed at the end of meiosis 2?

Answer 13

early spermatids

Question 14

How many spermatids are formed from one type B spermatogonium?

Answer 14

4

Question 15

What links the spermatids together and what is the purpose of it?

Answer 15

Cytoplasmic bridges - gives it a degree of synchronicity

Question 16

What process occurs to make sure clones are not all the same so there is individuality?

Answer 16

Meiotic chiasmata

Question 17

What is the name of the process where spermatids look more like a characteristic sperm and acquire morphology to enable them to fertilise an egg?

Answer 17

Spermiogenesis

Question 18

What secretes the acrosomal vesicle?

Answer 18

Golgi apparatus which has moved to proximal end of spermatid

Question 19

What is the final product of spermiogenesis?

Answer 19

Spermatozoa

Question 20

In the seminiferous tubueles what is occuring to make sure there are always developed sperm readily available?

Answer 20

Spermatogenic wave

Question 21

What are the 3 functions of the epididymis?

Answer 21

1) sperm concentration
2) sperm maturation
3) sperm storage

Question 22

What cells do LH stimulate in males and what do these cells produce?

Answer 22

Stimulate Leydig cells to produce testosterone

Question 23

What are Leydig cells analogous to in females?

Answer 23

Theca cells

Question 24

Does testosterone have negative or positive feedback on the hypothalamus?

Answer 24

Negative - less LH produced

Question 25

What cells do FSH bind to and what is the result of this?

Answer 25

Bind to Sertoli cells which stimulates the production of androgen receptors - needed for sperm development

Question 26

In males what are androgens converted to

Answer 26

5 alpha-dihydrotestosterone (a more potent form of testosterone)

Question 27

What percentage volume to seminal vesicles contribute to semen volume?

Answer 27

60%

Question 28

What nutrients does seminal fluid contain?

Answer 28

Fructose
Ascorbic acid (vit C - good antioxidant)
Prostaglandins
pH <7

Question 29

What percentage volume does the prostate contribute to semen?

Answer 29

20-30%

Question 30

What do Cowper’s/bulbourethral glands produce? and what volume of semen do they make up

Answer 30

Mucous to lubricate action of coitus - 5%

Question 31

What is the general aim of prostate drugs? (treatment of benign prostate hyperplasia/cancer)

Answer 31

To interrupt with androgen signalling as this is what the prostate needs to work

Question 32

Name a GnRH antagonist

Answer 32

Goserelin

Question 33

Name an androgen receptor antagonist

Answer 33

Bicalutamide

Question 34

Name a reductase inhibitor used to treat BPH/prostate cancer

Answer 34

Finasteride

Question 35

What is classed as a ‘normal’ sperm production?

Answer 35

> 15 million sperm per ml
40% motility
32% should have progressive motility
4% need to have normal morphology

Question 36

What is the term used to mean low sperm count?

Answer 36

Oligozoospermia

Question 37

What is aspermia?

Answer 37

complete absence of semen caused by retrograde ejaculation back into bladder

Question 38

What is azoospermia

Answer 38

complete absence of sperm - dysfunction of HPG axis, genetic conditions, chemotherapy

Question 39

What term is given to sperm with low motility?

Answer 39

Asthenozoospermia

Question 40

What name is given to sperm with abnormal morphology

Answer 40

Teratospermia

Question 41

name the physiological process of desire/arousal

Answer 41

Excitement > plateau > Orgasm/climax > resolution - males require an absolute refractory period

Question 42

What substance acts as a vasodilator of blood vessels of corpora cavernosa during erection?

Answer 42

Nitric oxide

Question 43

Other than NO what else vasodilates blood vessels to create an erection?

Answer 43

cyclic GMP

Question 44

What is detumescence?

Answer 44

end of stimulation - get muscles relaxing and end of erection

Question 45

What enzyme is responsible for breaking down cyclic GMP at the end of sensory stimulation?

Answer 45

Phosphodiesterase V (PDE5)

Question 46

Name the mechanism of action and use of Sildenafil

Answer 46

PDE5 inhibitor used to treat erectile dysfunction