Spermatogenesis and male infertility* Flashcards
(38 cards)
What does the y chromosome have
the sex determining region which assess development of testis from biopotential gonad
what does fetal testes secrete
testosterone
what are the two primitive genital tracts
wolffian and mullein ducts
what causes the development of the male internal genital tract
testosterone and mullerian inhibiting factor
wolffian ducts leads to what in males and what happens to mullerian ducts
repro tract
degenerate
what happens to wolffian ducts and mullerian ducts in females
degenerate
repro tract
when can male/female fetus be differentiated
around 16 weeks
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
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
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
where does spermatogenesis occur
where is testosterone produced from
seminiferous tubules
leydig cells
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
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
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
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
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
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
inhibin and activin are what
where are they secreted from
feedback on what
peptides
sertoli cells
inhibin inhibits FSH and activin stimulates
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
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
route of sperm
testes - epi - VD - ejacultory duct - urethra
what happens during an erection
blood fills corpora cavernosa (under PS control)
emission
contraction accessory sex glands and VD so semen expelled to urethra
ejaculation
contraction of smooth muscles or urethra and erectile muscles (symp control)
