Question

In human females, each time during maturation and release of the egg the inner wall of the uterus thickens. Is this thickening permanent? Give reasons.

Answer 1

Thickening of inner walls of the uterus:

1. In each menstrual cycle, an egg is released into the uterus for fertilization.
2. The process of releasing the egg by the ovary is known as ovulation.
3. During ovulation, estrogen thickens the endometrium. Progesterone prepares the uterus for pregnancy.
4. Fusion of male and female gamete results in the formation of zygote. The zygote develops into an embryo gradually to a fetus. This is the case of pregnancy.
5. If the egg is fertilized and the zygote is formed, this thickening provides adequate nutrition and protection for its growth.
6. In absence of fertilization, progesterone levels drop. This drop triggers the uterus to shed its inner linings as menstrual blood.
7. The thickening along with unfertilized egg is released through the vagina, which is known as menstruation.
8. So the thickening of the uterus wall is not permanent. The thickening is to provide nutrition for the development of the embryo in case of pregnancy.
9. In absence of pregnancy, the thickening is shed as menstrual blood.
10. Therefore the thickening of uterus walls during the menstrual cycle is not permanent.