When the follicle wakes up, it releases estrogen. When LH goes up, the LH surge occurs. LH causes follicle to release the ovum. Ovum travels through the tubes to uterus.
Empty follicle changes into corpus luteum.
Corpus luteum secretes estrogen and progesterone. When the progesterone drops, the endometrium collapses and menses begins. This stimulates the hypothalamus, and the process starts over. Not progesterone enough to counteract the high estrogen. No body fat to store estrogen.