Menstrual Cycle Flashcards
oogenesis
oocyte (4N) –> arrested un prophase I from birth til puberty –> meiosis I –> meiossis II
when does prim oocyte resume meiosis I?
upon LH surge
produces 2N secondary oocye and 2N polar body
arrests in meiosis II
when does secondary oocye resume meiosis II?
fertilization!
creates 1N fertilized ppcyte + 1N polar body
describe development of the follicle
primordial –> primary –> secondary –> graafian follice with atresia of neighboring follicles
which follice ovulates?
the dominant one
what are the four basic processes of the follicular phase?
1) follice development
2) upreg of LH/FSH receptors on theca/granulosa cells
3) increased estradiol levels –> proliferation of endo + watery thin cervical mucus
4) ovulation
how does estrogen feedback change during cycle?
has negative feedback on pituitary during follicular phase until it peaks, reverses and then has POSITIVE feedback –> LH surge
where does the corpus luteum appear from? what does it do?
it is the follicle AFTER the egg has been released
it secretes progesterone to get the endometrium nice and ready for implantation
what do increased levels of progesterone in luteal phase do?
- thick mucus
- tortuous spiral arteries and glandular secretions
- increase basal body temp
if fertilization does occur, the corpus luteum secretes what to maintain endo lining?
prog and bhCG for 9 weeks until placenta can produce its own
preantral follicles include:
primordial follicles
primary follicles –> **enter zona pellucida
secondary follicles
antral follicles include:
tertiary follicles
graafian follicles
name auto/paracrine factors involved in follicular maturation?
VEGF
activin –>
inhibin
what helps to determine the dominant follicle?
more: est, better blood supply, more FSH receptors, more granulosa proliferation, more aromatase activity, more inhibin
whats the 2 cell theory of sex steroid production?
you need two cell types to produce estradiol
1) thecas –> LH, produce androgens
2) granulosa cells –> convert androgens to estradiol
