Observe the diagram of menstrual cycle and answer the following questions:
(1) What is the period of menstruation?
(2) On which day does ovulation occur during menstrual cycle?
(3) During which period is corpus luteum active during menstrual cycle? Which hormones are secreted by corpus luteum ?
(4) In menstrual cycle which reproductive organs undergo changes?
(5) Which period is said to be period of regeneration of endometrium?
(6) Which period is said to be period of secretions of glands in the endometrium?

Answer:

1. 1 to 5 days is the period of menstruation.
2. Ovulation occurs on the 14th or 15th day.
3. The Corpus luteum is active till the 28th day of the menstrual cycle. During this time if there is no union of sperm and ovum, the corpus luteum degenerates. Corpus luteum secretes estrogen and progesterone.
4. The ovary and uterus change during menstrual cycle
5. In the menstrual cycle, days 5 to 14 are the period of regeneration of the endometrium.
6. The period of secretions of glands in the endometrium is 15 to 28 days.