Question

What happens to the wall of the uterus during menstruation?

Answer 1

Hint: Menstrual cycle is a regular physiological change in females which occurs at an average interval of 28 or 29 days and starts from 10-12 age and ends at 45-50 age normally. In menstruation vaginal discharge takes place from the endometrial lining of the uterine wall through the vagina.

Complete Answer:
The menstrual cycle is divided into three phases: menstrual, proliferative and secretory.
In the menstrual phase, the endometrium lining of the uterus wall breaks and passes out through the vagina with some blood, serous fluid and mucosal fragments.

Additional Information:
In the follicular and proliferative phase, the reduced concentration of ovarian and gonadotropin stimulates the hypothalamus to produce a gonadotropin-releasing hormone which activates the anterior pituitary and produces gonadotropin. Due to FSH the ovarian follicle becomes enlarged through proliferation and addition of thecal covering on the outside and development of antrum takes place at the centre. The growing granulosa secrete estrogen and a small amount of fibrin and after a week develop into one ovarian follicle and become functional.
The luteal or secretory phase begins after the occurrence of ovulation and it is of two types: corpus luteum and endometrium. In the corpus luteum the LH helps the graafian follicle to grow and the follicular cell get converted into lutein cells. This is known as luteinisation. In endometrium both LH and progesterone help in growth and thickening of endometrium and the endometrial wall become secretory. The uterine wall becomes ready for nourishing and anchoring the blastocyst in case of fertilisation.

Note:
The blood that presents inside the genital tract does not get a clot due to the presence of fibrinolysin therefore blood flows out normally and the menstrual phase occurs when the titre of ovarian and gonadotropin hormones is low.