Spermatogenisis Flashcards
what is the temperature of the sperm?
1.5-2.5 degrees below body temprature
what is the effect on the sperm when they enter the higher temperature of the vagina?
become activated - begin swimming
where does spermatogenesis occur?
in the seminiferous tubules
where are the seminiferous tubules located?
between the lymph and blood vessels, between the leydig cells of the testes
what are the leydig cells?
respond to LH curing the production of androgens - move to the Sertoli cells
what is the effect of androgens in the Sertoli cells?
when FSH binds, the androgens are converted to oestrogen and this maintains the population and increases spermatogenisis
what is the effect of exogenous androgens?
there is an increase in oestrogen, the HPG decreases FSH so there is decreased sertoli cells - therefore infertile with breast bud development
what is the purpose of the basement membrane in the sertoli cells?
site of primary germ cells - spermatogonia
what are the two routes of spermatogonia development?
mitosis to reform the germ cells
meiosis to form the spermatids
what is occurring in the change from secondary spermatocyte to spermatid?
elongation, loss of cytoplasm, movement of the cellular contents
what causes an erection?
parasympathetic release of VIP and NO
causes vasodilation
there is venule constriction
backflow of blood = engorgement
what is the mechanism of ejaculation?
sypathetics causes the sperm to enter the epididymus then the vas deferens then the urethra - gives 4-10 contractions coordinated with the glands
how much fluid is ejaculated?
1.5 to 6 ml
120 million sperm
which part of the sperm is most important to obtain on a sample? why?
the beginning - as it is most sperm rich
what secretions come from: bulbourethral gland?
pre-ejaculate to neutralise and lubricate the urethra - salt rich, clear and viscous
