The Menstrual Cycle

Purpose: to bring an egg to maturity and to prepare the reproductive system for pregnancy.

28 day cycle (on average)

Repeats continuously until menopause

Four Phases

1. Flow phase (5 days) – shedding of the endometrium (if no fertilization occurs)

Four Phases2. Follicular Phase (days 6-13) – development of

follicle within one of the ovaries

Follicles contain developing oocye (egg) and as they develop begin to secrete estrogen

Four Phases

3. Ovulation (day 14) – egg bursts from the ovary and the follicle cells develop into the corpus luteum

Four Phases

4. Luteal Phase (days 15-28) - development of the corpus luteum

Corpus luteum secretes both progesterone and estrogen. - Prepares uterus for an embryo

The Full Cycle