physiology of the male reproductive system Flashcards
function of testes
make testosterone and sperm
epididymis function
transport sperm from testes to vas deferenens - maturation of sperm
ductus deferenes fucntion
muscular tube travels from epididymis to pelvic cavity - mature sperm to urethra fro ejaculation
lined by cilated epithelium
corpus spongeosum function
surround urethra and open it for ejaculation - contain blood vessels
corpus cavernosum function
contains blood vessels fro erection
seminal gland function
produce constituent ingredient of semen
urethra
tube where urine and sperm pass
what is the function of Sertoli cells
nourish developing sperm cells and act as phagocytes consuming residual cytoplasm during spermatogenesis
in the testes where is sperm made
seminiferous tubules
what does the basal lamina around the seminiferous tubules provide
structural integrity
what cells found between the seminiferous tubules also called interstitial cells
leydig cells
Sertoli cells function
support sperm production
leydig cells function
produce testosterone
what is HPG axis
hypothalamus pituitary gonadal axis - as a system
what releases Gonadotrophin relating hormone
hypothalamus
activated by GnRH what does the pituitary release
FSH
LH
what does FSH stimulate
Sertoli cells
what does lh stimulate
leydig cells
what two things does Sertoli cells need to make ABP
testosterone and FSH stimulation
Androgen binding protein and testosterone combine to promote sperm production
what periphery effect does testosterone have
maintain libido
muscle and bone growth
secondary sexy characteristics
accessory gland maintenance
what type of feedback regulates testosterone
negative feedback
too much stop higher supply and inhibit GnRH and LH and FSH
what other hormone do Sertoli cell release that acts on pituitary to inhibit FSH
inhibin
spermatogenesis
production of mature spermatozoa
spermatocytogenesis
1st stage of Spermatogenesis
germ cell undergoes cell division to become immature spem/spermatid
spermiogenesis
2nd stage
maturation of immature sperm to mature sperm
two types of spermatogonia
A
B
What is the function of type A spermatogonia
replenish pool of spermatogonium - this is why males are fertile throughout adult life
function of type 2 spermatogonia
spermatogenesis - 70 days
spermiogenesis
remodelling and differentiation into mature sperm
4 stages of spermiogenesis
Golgi phase - Golgi body enzymes form acrosome
acrosomal phase - acrosome condense around nucleus
tail phase - centrioles elongate to form tail
maturation phase - loss of excess cytoplasm - aerodynamic
spermiation
process by which mature sperm are released from sertoli
how are sperm moved to epididymis
peristlallic contraction and sertoli testicular fluid
capacitation
process of making sperm fertile
what enzyme helps capacitation - produce in prostate gland
FPP- in seminal fluid
what female hormone produced in female repoT helps capacitation
heparin
do high levels of FPP prevent capacitation in male RT
yes - but after ejac the conc of FPP drops and female RT promotes capacitation
3 adaptations of the vagina that give best chance to sperm
cervix only penetrable at certain times of month - watery cervical mucus
oestrogen levels high
crypts in vag ( folds of epithelial cells) create a reservoir for spermatozoa - release sperm over several hours increasing chance
what is hypogonadism
diminished functional activity of the gonads ( testes and ovaries) result diminished production of sex hormones
testicular disease
disease of CNS of pituitary or hypothalamus
what is hypergonadotrophic hypogonadism
issue with the testes or ovaries because testosterone isn’t secreted so levels are low so sends signal to increase so GnRH if high but testes aren’t fucnting so low testosterone still FSH ADN LH would be high
hypogonadotrophic hypogonadism
low testosterone as low GnRH as problem with either hypothalamus and pituitary
what two things can cause a blockage in the spermatic cord
trauma - rugby
infection - chlamydia
what is hypospadias
opening of the urethra is on the underside of the pens instead of tip
function of prolactin in what it inhibits
high levels inhibits testosterone and associated with reduced libido and sexual dysfunction( unable to sustain erection)
So if someone has high FSH and LH (gonadotrophs) and low testosterone. wheres the problem?
Testes - therefore Hypergondaotrophic hypogonadism.
Would indicate issue with testicle – trauma, infection, CF, testicular failure
Why would FSH and LH be elevated?
Negative feedback
Note - testosterone levels could be normal-low – it takes time for testosterone to fall
someone has
Low FSH, LH
Low Testosterone
what is the problem
HYPOgonadotrophic hypogonadism
issue with hypothalamus or pituitary
Would indicate issue with either hypothalamus or pituitary gland:
– Congenital (Kallmann syndrome (KS) and idiopathic hypogonadotropic hypogonadism)
- Acquired (drugs, alcohol abuse, infectious lesions etc)
36 year old male presents to fertility clinic. He and his partner have been trying to conceive for several years but have been unsuccessful. He reports feeling disinterested about sex and often experiences erectile dysfunction. He also mentions experiencing headaches over the past six months which are refractory to treatment.
Examination is normal
High Prolactin
Low testosterone
Low LH, FSH
Hypersecretion of prolactin (pituitary tumours, drug induced)
Leads to inhibition of GnRH – reduces LH, FSH – leading to low testosterone – leads to erectile dysfunction and low libido
Hyperprolactinemia is very rare
what is prolactinoma and what is the knock on effect
So if someone has a prolactinoma, that is a tumour in the pituitary that secretes prolactin.
Prolactin has a negative feedback effect on the hypothalamus so it decreases the amount of GnRH released which decreases the amount of LH and FSH and decreases the testosterone.
what is a vasectomy
stops sperm getting into semen - vas deferens blocked or cut - 3 months then sperm won’t be In semen
