Question

What are the changes taking place in the uterine wall during menstrual cycle?

Answer 1

Menstrual cycle:

1. The female reproductive system passes through a regular monthly sequence of events called the menstrual cycle after attaining puberty.
2. The lining of the uterus (endometrium) is shed during this cycle.
3. The endometrium becomes thick in due course, for the implantation of the fertilized egg, upon failing that process the uterine wall breaks down and sheds from the body. This is called menstrual flow.

Phases of the menstrual cycle:

With each monthly cycle, the endometrium prepares itself to nourish a fetus. The four main phases of the menstrual cycle are:

1. Menstrual phase (elimination of the thickened lining of the uterus)
2. Follicular phase (ends with the formation of Graafian follicle)
3. Ovulatory phase (release of a mature egg from the surface of the ovary)
4. Luteal phase (ruptured follicle stays and becomes corpus luteum)

Changes in the uterine wall:

1. Luteal phase releases hormones, mainly progesterone and some estrogen. The rise in hormones such as estrogen and progesterone keeps the uterine lining thick and ready for a fertilized egg to implant.
2. If a fertilized egg implants in the lining of the uterus, it produces the hormones that are necessary to maintain the corpus luteum.
3. If pregnancy does not occur, the corpus luteum withers and dies, usually around day 22 in a 28-day cycle resulting in the drop of progesterone leading to shedding of the uterine lining.