Spermatogenesis and male infertility* Flashcards Preview

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

What does the y chromosome have

A

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

2
Q

what does fetal testes secrete

A

testosterone

3
Q

what are the two primitive genital tracts

A

wolffian and mullein ducts

4
Q

what causes the development of the male internal genital tract

A

testosterone and mullerian inhibiting factor

5
Q

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

A

repro tract

degenerate

6
Q

what happens to wolffian ducts and mullerian ducts in females

A

degenerate

repro tract

7
Q

when can male/female fetus be differentiated

A

around 16 weeks

8
Q
what is androgen insensitivity syndrome 
link
karyotype
whats happens in it
presentation
A

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
Q

where do the testis develop and drop to

why is it important that they descend

how is the testes raises/lowered

A

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
Q

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

A

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
Q

where does spermatogenesis occur

where is testosterone produced from

A

seminiferous tubules

leydig cells

12
Q

what are the roles of the sertoli cells

A

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

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

A

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

15
Q
what are FSH and LH
LH does what 
FSH does what
stimulated by what 
inhibited by what 
what is their production like
A

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
Q

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

A

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

17
Q

testosterone effect before birth
puberty
adult

A

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
Q

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

A

peptides
sertoli cells
inhibin inhibits FSH and activin stimulates

19
Q

what happens to spermatozoa after ejactulation

A
liquifies
capacitation
chemoattraction to oocyte - binds
acrosome reaction - exocytosis
hyperactivated motility 
penetration of egg coat and fusion with oocyte membrane 
zonal reaction
20
Q

what does epididymis and VD do
seminal vesicles
prostate
bulbourethral glands

A

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
Q

route of sperm

A

testes - epi - VD - ejacultory duct - urethra

22
Q

what happens during an erection

A

blood fills corpora cavernosa (under PS control)

23
Q

emission

A

contraction accessory sex glands and VD so semen expelled to urethra

24
Q

ejaculation

A

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

25
Q

definition of male infertility

A

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

26
Q

causes of male infertility

A

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

27
Q

endocrine causes of male infertility

A
pit tumours
hypothalamic - tumours, kallmans, anorexia
thyroid - hyper/hypo
DB
CAH
androgen insensitivity 
steroid abuse
28
Q

examination for male infertility

A

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
Q

semen analysis

A
volume 
density - numbers of sperm 
morality - what proportion are moving 
progression - how well they move
morphology
30
Q

extrinsic factors for semen analysis

A
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
Q

further assessment

A

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

testicular biopsy, scrotal scan - dependant on scan

32
Q

obstructive clinical features

endocrine features

A

normal testicular volume
normal secondary sexual characteristics
VD may be absent

normal LH, FSH, testosterone

33
Q

non obstructive dx

endocrine

A

low testicular volume
reduced secondary sexual characteristics
VD present

high LH, FSH and low testosterone

34
Q

treatment of male infertility life style

A
frequent sex
alcohol <4 units/day
stop smoking 
BMI <30
avoid tight fitting underwear 
vit C/zinc
35
Q

IUI indication
procedure
preg rate

A

mildly reduced sperm count

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

15% per treatment cycle

36
Q

ICSI indications
procedure
preg rate

A

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

37
Q

surgical sperm aspiration indication
procedure
success rate at obtaining sperm

A

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

38
Q

donor sperm insemination indications
procedure
preg rate

A

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