Ogenesis, spermatogenesis, fertilisation, and implantation Flashcards
where is testosterone produced
leydig cells
list 2 of the effects before birth testosterone has
masculinises reproductive tract and external genitalia
promotes descent of testes into the scrotum
list secondary sexual characteristics caused by testosterone
induces characteristic male pattern of hair growth
enlarges larynx
thickens skin
causes male body shape
what does testosterone do to the epiphyseal plates
closes them
where is sperm produced
seminiferous tubules
what types of cells support spermatogenesis
sertoli cells
recite the stages of sperm production in sertoli cells
spermatogonium
primary spermatocyte
secondary spermatocyte
spermatid
spermatozoa
what hormone is required for both stages (mitotic and meiotic)
testosterone
how many chromosomes does a primary spermatocyte have
46
ow many chromosomes does a secondary spermatocyte have
23
how many chromosones does a spermatid have
23
in what stage are spermatids produced
2nd meiotic division
in what stage are secondary spermatocytes produced
1st meiotic division
in what stage are primary spermatocytes produced
mitotic division
what hormone is required for the spermatids being converted to spermatozoa
FSH
what happens when spermatids are converted to spermatozoa
removal of unnecessary cellular components and rebuilding into specialised motile spermatozoa
what is the purpose of the acrosome
contains enzymes needed for penetration of the ovam
what cells are responsible for secretion of seminiferous tubule fluid
sertoli cells
what does inhibin do in spermatogenesis
regulates FSH secretion ( negative feedback loop)
what hormone rises in the menapause
FSH
what hormones fall in menapause
oestrogen, progesterone, and inhibin
what are the two phases in the ovarian cycle
follicular phase
luteal phase
in what phase does ovulation occur
follicular phase
in what phase does the development of the corpus luteum occur
luteal phase
until puberty 1^0 follicles degenerate into what
scar tissue (atresia)
what does the follicular phase end with
ovulation
follicular cells left behind after ovulation undergo what
leutanisation (transformation into corpus luteum)
what hormones does the corpus luteum secrete
progesterone and oestrogen
after ovulation how many days does the corpus luteum grow
8-9 days
what forms if there is no fertilisation
corpus albicans
what signals the start of a new follicular phase
degeneration of the corpus luteum
if fertilisation occurs what hormones does the corpus luteum produce
oestrogen and progesterone
what days does oestrogen exert negative feedback
1-12 days
what days does oestrogen exert positive feedback
12-14 days
what causes the LH surge
positive feedback from oestrogen
without progesterone what happens to the uterine lining
sloughs off and then menstration occurs
what is the route of sperm
testes
epidydmis
vas deferens
ejeaculatory duct
urethra
freshly ejaculated sperm are not capable of ehat
fertilisation
what needs to happen before sperm are capable of fertilisation
capacitation
what happens when sperm go undergo capacitation
surface of sperm altered by removal of glycoprotein coat
tail movements become whip like
cAMP levels rise to promote acrosomal reactioon
fertilising sperm penetrate what in the egg
penetrate the corona radiata
what receptors do sperm bind to on the egg
ZP3
where are the ZP3 receptors
zona pellucida
binding to ZP3 triggers what
acrosome reaction
the sperm nucleus enters where
ovum cytoplasm
sperm stimulate release of what ion which inactivate ZP3
Ca2+
what chemical is released from the ovum to attract sperm
allurin
inactivation of the ZP3 receptors causes blocking of what
polyspermy
what cells are present on the blastocyst
trophoblast
how does the blastocyst implant on the uterine lining
cords of trophoblastic cells
what are the single layer of cells surrounding the blastocyst
trophoblast
how can you tell when implantation has finished
blastocyst is completely buried in the endometrium
what is the placenta derived from
trophoblast and decidual tissue
where is hCG produced from
blastocyst
what does hCG do to the corpus luteum
prolongs life
what triggers duct development
oestrogen
what trtiggers lobule formation
progesterone