General overview of lecture:The fertility of the mature human female is cyclic. The release
from the ovary of a mature female germcell or ovum occurs at a distinct phase of the
menstrualcycle. Cyclic changes in luteinizing hormone (LH)and follicle-stimulating hormone
(FSH)from the pituitarygland and estradiol and progesterone from the ovaries controlthe
secretion of ovarian steroid hormones, estradiol andprogesterone, and the subsequent release of
an ovum during the menstrual cycle. The cyclic changes in steroid hormone secretion cause
significant changes in the structureand function of the uterus in preparing it for the reception of a
fertilized ovum. At different stages of the menstrual cycle,progesterone and estradiol exert
negative- and positivefeedback effects on the hypothalamus and pituitary
gonadotrophs,generating the cyclic pattern of LH and FSH releasecharacteristic of the female
reproductive system. The hormonalevents during the menstrual cycle are delicately
synchronized;thus, stress and environmental, psychologic, and social factors can readily affect
the menstrual cycle.