Oogenesis, egg formation -> mature eggs within the ovary are contained within the Graafian follicle -> menstrual period, 1-5 days, epithelial lining of the uterus is shed -> one Graafian follicle erupts through the wall of the ovary during the post menstrual phase (6-13), OVULATION -> ovum migrates into fallopian tubes -> per-menstrual phase (15-28), the uterine lining anticipates implantation, endometrium grows thicker-> if spermatozoa are present, fertilization MAY occur and pregnancy begins -> if fertilization does NOT occur, hormone levels drop and after day 28, another menstrual phase begins