Name: Fertilization
Uploaded: 2019-07-19
Duration: 1 min 38 s
Description: This video discusses one of the essential concepts of the human reproductive system: fertilization. It establishes that in fertilization, the male and the female gamete fuse to form a zygote and highlights the concepts of internal and external fertilization.

Question

What is menstrual cycle? Describe the cycle in human with a reference to cyclic changes in the ovary and uterine endometrium.

Accepted Answer

Menstruation is the natural process of regular blood discharge from the body of a female. The cycle of events ( $28 ‐ 29$ days cycle) starting from the first day of menstruation to the starting of next menstruation is called the menstrual cycle. It is regulated by hormones like FSH and LH.

It includes the three important phases:-

Menstrual phase: Menstruation is the blood flow due to the breakdown of the endometrium lining of the uterus and blood vessels.

Follicular phase or Proliferative phase: The proliferative phase includes the development of primary follicles. In this phase, gonadotropin releases LH and FSH in an increased amount. During the $14^{t h}$ day of the cycle the level of LH and FSH rises that induces rupture of the Graafian follicle and thereby release of ovum called ovulation.

The luteal phase or Secretory phase: This phase occurs after ovulation. This phase helps in the transformation of the remaining parts of the Graafian follicle into the corpus luteum. It secretes the hormone progesterone, which is responsible for the thickening of the endometrium.

What is menstrual cycle? Describe the cycle in human with a reference to cyclic changes in the ovary and uterine endometrium.

Important Questions on Human Reproduction

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