CBSE Class 10 Answered
1. Menses takes place on the 3rd –5th day of the menstrual cycle of 28 days. The production of LH is considerably reduced. This causes degeneration of the corpus luteum and reduction in the production of progesterone and oestrogen.
2. The follicular phase begins on the 6th and lasts up to the 13th or 14th day in a 28- day menstrual cycle. FSH stimulates the ovarian follicle to secrete oestrogen.
3. At about the 14th day of the menstrual cycle, both FSH and LH attain a peak level. Rapid secretion of LH induces rupturing of the Graafian follicle and the release of the ovum (ovulation).
4. The luteal phase begins on the 15th and lasts up to the 28th day in a 28 -day menstrual cycle. LH causes ovulation. The remaining cells of the ovarian follicles are stimulated by LH to develop the corpus luteum.
The corpus luteum secretes a large amount of progesterone which stimulates the uterine glands to produce an increased amount of watery mucus