PHYSIOL 1 Lecture Notes - Lecture 17: Anterior Pituitary, Corpus Albicans, Pituitary Gland
Document Summary
Levels are low until puberty ages 8-13 and is marked by a dramatic rise in estrogen levels. This is caused by an increased secretion of gonadotropin releasing hormone from the hypothalamus increases the release of fsh/lh from the anterior pituitary. The pulsatile nature causes a positive feedback at the pituitary that produces the lh surge to cause ovulation. They begin to peak around the ages of 40-50. The menstrual cycle becomes irregular at this age and ovulation may not occur during some cycles. Eventually, the cycles stop altogether around the age of 50. The period marked by decreased estrogen production/cessation of the menstrual cycle is called menopause. Roughly 400 primary follicles grow into mature follicles and ovulate, while many hundreds of thousands degenerate. Menopause seems to be caused by a decrease in primary follicle numbers in the ovaries. With less follicles, less estrogen can be produced.
