Arrange the various ovarian events occurring during a menstrual cycle in sequence:

(A) Maturation of follicle
(B) Development of primary follicle
(C) Ovulation
(D) Transformation of graafian follicle into corpus luteum

Choose the correct answer from the options given below:

(B), (A), (C), (D)

The correct answer is Option (2) → (B), (A), (C), (D)

(B) Development of primary follicle

(A) Maturation of follicle

(C) Ovulation

(D) Transformation of graafian follicle into corpus luteum

The reproductive cycle in the female primates (e.g. monkeys, apes and human beings) is called menstrual cycle. The first menstruation begins at puberty and is called menarche. In human females, menstruation is repeated at an average interval of about 28/29 days, and the cycle of events starting from one menstruation till the next one is called the menstrual cycle.

One ovum is released (ovulation) during the middle of each menstrual cycle. The menstrual phase is followed by the follicular phase. During this phase, the primary follicles in the ovary grow to become a fully mature Graafian follicle and simultaneously the endometrium of uterus regenerates through proliferation. These changes in the ovary and the uterus are induced by changes in the levels of pituitary and ovarian hormones . 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 induces rupture of Graafian follicle and thereby the release of ovum (ovulation).

The ovulation (ovulatory phase) is followed by the luteal phase during which the remaining parts of the Graafian follicle transform as the corpus luteum.The corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium. Such an endometrium is necessary for implantation of the fertilised ovum and other events of pregnancy.