Some of these incoming fibers go to the motor nucleus of the trigeminal nerve (V), bypassing the pathways for conscious perception. The jaw jerk reflex is an example; tapping the jaw elicits a reflex closure of the jaw in the same way that tapping the knee elicits a reflex kick of the lower leg.
FSH stimulates the production of eggs and LH stimulates the release of the egg. FSH and LH are produced by the pituitary gland in the brain. There are four stages in the menstrual cycle. Stage 1. Days 1-4. Menstruation (bleeding) occurs. The lining of the uterus disintegrates and is shed. This is due to low levels of progesterone. Stage 2. Days 4-14. The uterine lining grows back.
When estrogen peaks it causes an LH surge which leads to ovulation (release of egg from follicle) and causes the corpus luteum to develop. The corpus luteum produces estrogen and progesterone, which promotes growth and maintenance of the uterine lining (endometrium). When the corpus luteum deteriorates, due to a drop in LH, estrogen production decreases. This triggers menstruation.