• Define menarche and menopause

MENARCHE - end of puberty and marks beginning of potential fertility – maturation of GnRH pulsatility so primarily hypothalamic

MENOPAUSE - occurs around 45 - 55 yrs (average 51 yrs ) and marks end of natural fertility

• Explain the role of gonadotrophic hormones in the development of ovarian follicles and the corpus luteum

GONADOTROPHIC ELEASING HORMONES causes release of LH and FSH

• Describe the effects of FSH and LH in the early and mid-follicular phases of the menstrual cycle

FSH starts to increase and stimulate a group of follicles within the ovary to develop further, the majority will die except from one which will develop into a follicle that will release the oocyte. it increases just before ovulation to ensure that there is a graphian (mature) follicle available that is able to release the oocyte during ovulation

LH keeps a relatively steady gradient of slightly increasing until the end of the proliferation phase and just before ovulation its negative feedback changes to positive feedback and there is a MASSIVE spike in LH after ovulation int rapidly degrades down again to its previous level.

the LH surge actually triggers ovulation of the mature follicle which ejects the egg