Spermatogenesis and male infertility* Flashcards Preview

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Flashcards in Spermatogenesis and male infertility* Deck (38):
1

What does the y chromosome have

the sex determining region which assess development of testis from biopotential gonad

2

what does fetal testes secrete

testosterone

3

what are the two primitive genital tracts

wolffian and mullein ducts

4

what causes the development of the male internal genital tract

testosterone and mullerian inhibiting factor

5

wolffian ducts leads to what in males and what happens to mullerian ducts

repro tract
degenerate

6

what happens to wolffian ducts and mullerian ducts in females

degenerate
repro tract

7

when can male/female fetus be differentiated

around 16 weeks

8

what is androgen insensitivity syndrome
link
karyotype
whats happens in it
presentation

testicular feminisation
congenital insensitivity to androgens

x linked

male karyotype 46XY

testis develop but do not descend - androgen induction of wolffian duct does not occur but mullerian inhibition does occur

external genitilia female, absence of uterus and ovaries with short vagina
present at puberty with primary amenorrhoea and lack of pubic hair

9

where do the testis develop and drop to

why is it important that they descend

how is the testes raises/lowered

abdominal cavity and drop into scrotal sac before birth (androgen dependant)

lower temp outside to facilitate spermatogenesis

nervous reflexes trigger dartos muscle contraction i scrotal sac to lower/raise according to external temperature

10

what is cryptorchidism
what does it do to the sperm count
does it affect fertility
what operation should be done

individual has reached adulthood and testes have not descended

reduced sperm count

if unilateral then usually fetile

if under 14 then orchideopexy to reduce the risk for testicular germ cell cancer
if adult then orchidectomy

11

where does spermatogenesis occur
where is testosterone produced from

seminiferous tubules
leydig cells

12

what are the roles of the sertoli cells

form a blood testes barrier - protects sperm form AB attack, provides suitable fluid composition which allows later stages of sperm development

provides nutrients for developing cells

phagocytosis - removes surplus cytoplasm from packaging process and destroy defective cells

secrete seminiferous tubule fluid - used to carry cells to epididymis

secrete androgen binding globulin - binds testosterone so concentration remains high in lumen - essential for sperm production

secrete inhibit and action hormones - regulates FSH secretion and controls spermatogenesis

13

FSH and testosterone does what
inhibin does what
what do sertoli secrete
LH does what
testosterone leads to what
dihydrotestosterone does what

stimulates spermatogenesis
decreases secretion of FSH
ABG and inhibin
stimulus testosterone secretion
decreases release of GnRH and LH
enlargement of male sex organs and secondary sexual characteristics and anabolism

14

GnRH is a what type of peptide
where is it released form and how often
leads to what
what inhibits it

decapeptide
hypo in bursts every 2-3 hours begins age 8-12
Ant pit to produce FSH and LH
testosterone

15

what are FSH and LH
LH does what
FSH does what
stimulated by what
inhibited by what
what is their production like

glycoproteins
acts on leading cells - regulates testosterone secretion
acts on sertoli cells to enhance spermatogenesis and regulate negative feedback from inhibin
GnRH
testosterone
non-cyclical unlike females

16

where is testosterone produced from
what kind of steroid hormone is it
secretes into where for what
what does it have a negative feedback on

produced in leydig cells
steroid hormone derived form cholesterol
secreted into blood and seminiferous tubules for sperm production
hypo and pit gland

17

testosterone effect before birth
puberty
adult

masculinises repro tract and promotes descent of testes tract

promotes puberty and male characteristics

controls spermatogenesis, secondary sexual characteristics, libido, penile erection, aggressive behaviour

18

inhibin and activin are what
where are they secreted from
feedback on what

peptides
sertoli cells
inhibin inhibits FSH and activin stimulates

19

what happens to spermatozoa after ejactulation

liquifies
capacitation
chemoattraction to oocyte - binds
acrosome reaction - exocytosis
hyperactivated motility
penetration of egg coat and fusion with oocyte membrane
zonal reaction

20

what does epididymis and VD do
seminal vesicles
prostate
bulbourethral glands

exit route from test to urethra, concentrate and store sperm, rite for sperm maturation

produce semen into ejaculatory duct, supply fructose, secrete prostaglandins (motility), secrete fibrinogen (clot precursor)

produces alkaline fluid (neutralises vaginal acidity), produce clotting enzymes to clot semen within female

secrete mucus to act as lubricant

21

route of sperm

testes - epi - VD - ejacultory duct - urethra

22

what happens during an erection

blood fills corpora cavernosa (under PS control)

23

emission

contraction accessory sex glands and VD so semen expelled to urethra

24

ejaculation

contraction of smooth muscles or urethra and erectile muscles (symp control)

25

definition of male infertility

infertility resulting from failure of the sperm to normally fertilise the egg
usually associated with abnormalities in semen analysis

26

causes of male infertility

idiopathic - commonest
obstructive - CF, vasectomy, infection
non constructive - congenital (cryoptorchadism), infection mums, chemo/radio, tumour, genetic, semen abnormality, systemic, endocrine

27

endocrine causes of male infertility

pit tumours
hypothalamic - tumours, kallmans, anorexia
thyroid - hyper/hypo
DB
CAH
androgen insensitivity
steroid abuse

28

examination for male infertility

testicular volume pre pubertal 1-3mls adults 12-25mls
presence of VD and epi
penis (urethral orifice)
presence of any varicocele/other scrotal swelling

29

semen analysis

volume
density - numbers of sperm
morality - what proportion are moving
progression - how well they move
morphology

30

extrinsic factors for semen analysis

completeness of sample
period of abstinence
condition of transport
time between production and assessment
natural variations between samples
health of man 3 months before production

31

further assessment

release semen analysis 6 weeks later
endocrine profile
chromosome analysis, CF screen

testicular biopsy, scrotal scan - dependant on scan

32

obstructive clinical features
endocrine features

normal testicular volume
normal secondary sexual characteristics
VD may be absent

normal LH, FSH, testosterone

33

non obstructive dx
endocrine

low testicular volume
reduced secondary sexual characteristics
VD present

high LH, FSH and low testosterone

34

treatment of male infertility life style

frequent sex
alcohol <4 units/day
stop smoking
BMI <30
avoid tight fitting underwear
vit C/zinc

35

IUI indication
procedure
preg rate

mildly reduced sperm count

semen sample prepared to produce concentrated sperm sample. inseminated into uterine cavity around time ovulation

15% per treatment cycle

36

ICSI indications
procedure
preg rate

very low sperm count
sperm injected into stripped oocyte obtained during IVF
30% per cycle

37

surgical sperm aspiration indication
procedure
success rate at obtaining sperm

azoospermia
sperm aspirated surgically then injected into oocyte ICSI
95% in obstructed azoospermia and 50% in non obstructive

38

donor sperm insemination indications
procedure
preg rate

azoospermia or very low sperm count, genetic conditions, infective conditions

sperm donors matched for recipient characteristics and screened for genetic conditions and STId

15% per cycle