WHAT HAPPENS IN OVULATION AND HOW IT IS DIFFRENT FROM MENSTRUAL CYCLE?

CBSE Class 12-science Answered

WHAT HAPPENS IN OVULATION AND HOW IT IS DIFFRENT FROM MENSTRUAL CYCLE?

Asked by Shahwar | 07 Jun, 2015, 10:46: PM

Expert Answer

The level of estrogen causes a rapid rise in luteinising hormone.This rise of LH causes the dominant follicle to rupture and release the mature egg from the ovary, from where it enters the fallopian tube. This process is known as ovulation.

(i)LH causes ovulation. The remaining cells of the ovarian follicles are stimulated by LH to develop the corpus luteum.

(ii)The corpus luteum secretes a large amount of progesterone which stimulates the uterine glands to produce an increased amount of watery mucus.

(iii)The secretions of watery mucus by the vaginal glands and the glands of the fallopian tube
also increase.

(iv)Progesterone also maintains the endothelium which is necessary for the implantation of the fertilised ovum and other events of pregnancy.

(v)In the absence of fertilisation, the corpus luteum degenerates which causes disintegration of the endothelium, leading to menstruation and the start of a new cycle.

The ovulation is a phase of menstrual cycle alongwith menstrual phase, proliferative phase and secretory phase.

Menstrual Phase

(i)Menses takes place on the 3^rd–5^th day of the menstrual cycle of 28 days.

(ii)The production of LH is considerably reduced.

(iii)This causes degeneration of the corpus luteum and reduction in the production of progesterone and oestrogen.

(iv)The uterine endometrium breaks down and menstruation starts.

(v)Cells of the endometrium, secretions, blood and the unfertilised ovum constitute menstrual flow.

Answered by Sivanand Patnaik | 08 Jun, 2015, 09:07: AM