spermatogenesis

Question 1

what are the two compartments of the seminiferous tubules

Answer 1

intratubular compartment
peritubular compartment (interstitial space)

Question 2

what cells surround the developing sperm

Answer 2

sertoli (sustentacular)

Question 3

what is found in the interstitial space of the seminiferous tubules

Answer 3

Leydig cells

blood and lymph vessels

Question 4

what is the purpose of the blood testis barrier

Answer 4

prevents immune reaction to spermatozoa

separates fluid of different composition

Question 5

what are the 3 stages of sperm production

Answer 5

mitosis
meiosis
cell modeling (spermiogenesis)

Question 6

how often does spermatogenesis happen

Answer 6

every 16 days

Question 7

how often does the first mitotic division happen

Answer 7

every 74 days

Question 8

what happens at the end of differentiation

Answer 8

cytoplasmic links broken
spermatozoa released into tubule lumen
sperm are virtually immobile

Question 9

what does the acrosome contain

Answer 9

enzymes for fertilisation

Question 10

what does the midpiece contain

Answer 10

mitochondria

Question 11

where does spermatogenesis begin

Answer 11

basement membrane

Question 12

how many spermatogonia do males have

Answer 12

finite number but can undergo mitosis indefinitely

Question 13

where do spermatids go after production

Answer 13

fluid secreted by sertoli cells flushes them through from seminiferous tubules to rete testes to epididymis

Question 14

at what point are the sperm able to move

Answer 14

when they reach the tail of the epididymis

Question 15

what is capacitation

Answer 15

occurs in female genital tract
takes approx 4 hours
glycoprotein coat is stripped
this causes hyperactivation and head is able to initiate the acrosome reaction

Question 16

what proportion of sperm must be normal in order for in vitro fertilisation to occur

Answer 16

15% at least

Question 17

what is normal sperm count

Answer 17

50 -150 x10^6/ ml

i.e. approx 100 million

Question 18

what sperm count is defined as sub fertile

Answer 18

fewer than 20 million

Question 19

what proportion of sperm from a normal donor show abnormalities

Answer 19

30%

Question 20

what is oligozoospermia

Answer 20

low sperm count

Question 21

what is the name for absence of sperm in ejaculate

Answer 21

azoospermia

Question 22

what is the name for low sperm motility (fewer than 50% are moving)

Answer 22

asthenozoospermia

Question 23

what is the name for a high proportion of abnormally shaped sperm

Answer 23

teratozoospermia

Question 24

what are antisperm antibodies

Answer 24

abnormal immune response to sperm

Question 25

what is testosterone converted to

Answer 25

dihydrotestosterone or estrogens

Question 26

what cells produce estrogens

Answer 26

sertoli and leydig

Question 27

what cell produces inhibins (controls hormone levels)

Answer 27

sertoli cells

Question 28

what cell produces oxytocin

Answer 28

Leydig cells | causing contraction of smooth muscle of the genital tract

Question 29

what are the stages in steroid hormone biosynthesis

Answer 29

``` acetate cholesterol progesterone testosterone estrogens ```

Question 30

what happens if circulating testosterone is low

Answer 30

fewer cells undergo divisions but process takes the same length of time

Question 31

how does the anterior pituitary gland control testicular function

Answer 31

secretes gonadotrophins from gonadotroph cells

Question 32

what controls pituritary gonadotrophs

Answer 32

hypothalamus which secretes gonadotrophin releasing hormone

Question 33

what is the blood supply of the hypothalamus and pituritary

Answer 33

inferior and superior hypophyseal artery

Question 34

where are LH and FSh produced (gonadotrophs)

Answer 34

anterior pituitary- basophilic cells

Question 35

where are lactotrophs (prolactin) produced

Answer 35

acidophillic cells in the anterior pituitary gland

Question 36

what type of molecule are gonadotrophs

Answer 36

glycoprotein

Question 37

what type of molecule are lactotrophs

Answer 37

polypeptides

Question 38

what does the posterior pituritary secrete

Answer 38

arginine vasopressin (AVP) aka ADH and oxytocin (peptides)

Question 39

what controls LH and FSH secretion

Answer 39

GnRH

Question 40

what are the features of GnRH

Answer 40

GnRH is released into the portal blood in pulses every hour GnRH must be pulsatile or it is ineffective

Question 41

what pulse style favours LH synthesis and secretion

Answer 41

high amplitude and frequency

Question 42

what pulse style favours FSH

Answer 42

Low pulse amplitude and frequency

Question 43

what is the function of LH in males

Answer 43

stimulates testosterone from Leydig cells

Question 44

how does FSH affect sperm production

Answer 44

essential for maintaining sperm production at its normal level acts on sertoli cells

Question 45

what is the function of prolactin in males

Answer 45

enhances LH receptors in leydig cells which increases testosterone and spermatogenesis

Question 46

what hormones are produced by Leydig cells

Answer 46

oestrogen oxytocin testosterone

Question 47

what hormones are produced by sertoli cells

Answer 47

oestrogen | inhibins

Question 48

what is the function of ABP, androgen binding protein

Answer 48

binds to androgens in the testes which increases their concentration