UPNS 337 - OB Exam 1 Study Guide.

UPNS 337 - OB Exam 1 Study Guide/UPNS 337 - OB Exam 1 Study Guide. Review on Assessment and Health Promotion Describe the menstrual cycle in relation to hormonal, ovarian, and endometrial responses. o Menstrual cycle controlled by feedback of 3 following systems o Hypothalamic-pituitary cycle Low estrogen and progesterone levels at end of cycle stimulate hypothalamus to release Gonadotropin-releasing hormone (GnRH) GnRH stimulates anterior pituitary to secrete FSH - stimulates development of ovarian follicles and their production of estrogen LH – release of LH and small peak of estrogen (day 12) precede expulsion of ovum by follicles, levels peak at day 13,14 If no implantation, regression of corpus luteum = estrogen and progesterone decrease and again stimulate hypothalamus to release GnRH Ovarian cycle Pre-ovulation phase Before ovulation, 1-30 follicles begin to mature under influence of FSH and estrogen Surge of LH affects selected follicle and oocyte matures, ovulation occurs, empty follicle transforms into corpus luteum Ovulation Phase Estrogen levels decrease, 90% of women experience small amount of withdrawal bleeding Luteal Phase