The events involved in the menstrual cycle are menstrual phase, follilcular phase, ovulatory phase and luteal phase. In follicular please there is development of follicles in ovary This phase is also called as proliferative phase as there is proliferation of endometrium in uterus. It last for about 14 days. Lining of the uterus and fallopian tubes proliferates.
A graafian follicle grows, matures and secretes oestrogen. It ruptures to release its egg (secondary oocyte) after about 14 days. The secretion of gonadotropins (LH and FSH) increases gradually during the follicular phase, and stimulates follicular development as well as secretion of estrogens by the growing follicles.
Both LH and FSH attain a peak level in the middle of cycle (about 14th day). Rapid secretion of LH leading to its maximum level during the mid-cycle called LH surge that induces rupture of Graafian follicle and thereby the release of ovum (ovulation). The follicular phase ends with ovulation.