Basics of Reproductive Physiology Flashcards
what is the order of progression to a mature egg in the ovary?
primordial follicle > vascular follicle > mature grafian follicle with a central antrum > ovulation (the release of the egg [oocyte]) > corpus luteum (CL)> curopus albicans
what day does LH and FSH (gonadothrophic hormones) peak at?
14 (before 14 is the follicular phase and after is the luteal phase)
name the ovarian hormones
oestrogen, progesterone, inhibin A and B
categorise the phases and give the days of the ovarian cycle
0-7 Menses, 7-14 proliferative phase, 14-28 secretory phase
when does each ovarian hormone peak?
progesterone in the secretory phase after day 14, oestrogen peaks at day 14 then troughs, inhibin B peaks just after eostrogen oeaks around day 16 then rapidly troughs, inhibin A stays stable at low levels then peaks slightly as progesteorn peaks. FSH and LH peaks at ovulationn
What is the role of GnRH?
stimulate LH and FSH secretion from the anterior pituitary
what is the role of FSH
stimulate follicular recruitment and development
what is the role of LH
Maintain dominant follicle, induce follicular maturation and ovulation, stimulate corpus leuteum function
what is the role of Oestrogen (Oestradiol)
supports secondary female sexual characteristics and reproductive organs. -ve feedback control of LH and GnRH, except for in the late follicular phase (this is under positive contro of a LH surge). Stimulates proliferative endometrium and negative control of FSH.
WHERE IS OESTRADIOL RELEASED FROM?
Granulosa cells
what is the role of progesterone?
Maintains secretory endometrium. -ve feedback control of HPO
Where is progesterone released from?
Corpus luteum
how many follicles mature with each menstrual cycle?
4 to 10
what happens in the ovary to allow oogonia to become a secondary oocyte? Oogenesis…
oogonia mitoticly dividesgiving two primary oocytes, thhese then divide by meiosis forming 2 secondary oocytes with 23 chromosomes. LH SURGE STIIMULATES THIS PROCESS. Oognium are stem cells in the ovaries. They undergo mitotic division to produce primary oocytes which is completed at or shortly after birth. Meiosis starts but arrested in the prophase. Group of primary oocytes are hormone responsive in each cycle of which one grows to complete first meiotic division and release a haploid secondary oocyte at ovulation. The extra genetic material is released as the first polar body Secondary oocyte completes second meiotic division when fertilised by a sperm to form the mature ovum and second polar body.
what does oestrogen target?
CNS, AP, vagina, cervix, fallopian tubes, uterus, fat distriibution, mammary glands, bone maturation and turnover.
what happens in Sertoli cells to form sperm?
spermatogenesis: spermatogonia mitoticly divides forming a primary spermatocyte, this undergoes meiosis forming 2 secondary spermatocytes with 23 chromosomes each. Then there is a second meiotic division forming spermatids (spermiogenesis) with 23 chromosomes each, these then become sperm cells.
H-P-O AXIS…
hypo releasses GnRH acts on the pituitary - fsh and lh released these act on the ovaries which then release progesterone and oestrogen which act upon the uterus
