Ovarian Cycle

Follicular Phase

(Days 1-14) Estrogen + progesterone levels are low GnRH (from hypothalmus) stimulates release of FSH + LH (from anterior pituitary) FSH + LH stimulate development of ovarian follicles Developing follicles secrete estrogen Initially: low estrogen levels inhibit further FSH + LH release (negative feedback) Later in development: high estrogen levels stimulate FSH + LH release (positive feedback) "LH Surge" causes ovulation of egg from Graffian follicle on Day 14

Luteal Phase

(Days 15-28) Corpus luteum forms (due to high LH) & functions as an endocrine gland => secretes estrogen + progesterone Estrogen + progesterone feedback and cause FSH + LH levels to fall => No further follicle development => If egg not fertilized, corpus luteum starts to degenerate (because of low LH)

Ovarian Cycle

Ovarian cycle = cycle of egg maturation 28-day cycle During cycle, the most mature follicle (Graffian follicle) releases oocyte (egg) when LH levels surge Two phases: Follicular phase (Days 1-14) Luteal Phase (Days 15-28)