What is menstrual cycle? Describe the different phases in it.

Explanation

MENSTRUATION: It is a normal female periodic cycle of discharge of blood due to rupturing of the endometrium of the uterus. The period of menstrual cycle is about 28 days. The menstrual cycle may be divided into four phases.
(1) Menstrual Phase: It is also called menses. It is a normal female.periodic cycle of discharge of blood due to rupturing of the endometrium of the uterus. Also unfertilised egg and ruptured tissue of endometrium is discharged. It lasts for about five days of the cycle.
(2) Pre ovulatory Phase / Follicular phase (Proliferative phase): Here regeneration and thickening of endometrium of the uterus occurs. Also this phase is characterized by the transformation of the primary follicle into mature Graafian follicle under the influence of FSH. The secretion of gonadotropins (LH and FSH) increases gradually during the follicular phase. It takes about 6 to 13 days in a 28 day cycle.
(3) Ovulation / Luteal phase (Secretory phase): During this process ovum is released from ovary in the pelvic cavity and the process is called ovulation. It occurs approximately on the 14th day of menstrual cycle. It is a phase in which both LH and FSH are at the peak level and there is an LH surge.
(4) Post Ovulation Phase : It is also known as a luteal phase. It lasts from 15th to 28 in a menstrual cycle. After ovulation. LH stimulates the development of corpus luteum which starts secreting progesterone progesterone prepares the endometrium of the uterus to receive the fertilized ovum. However, if fertilization does not occur the corpus luteum degenerates and becomes the corpus albicans.