Question

What is the process called when the secondary oocyte is expelled from the ovary?

Answer 1

Oogenesis:

1. The formation of mature female gametes is called oogenesis.
2. This process starts during embryonic development in the mother's womb.
3. The gamete mother cells called oogonia are formed within the fetal ovary after no more cells are added to the oogonia after birth.
4. The oogonia undergo mitotic division to form a primary oocyte.

Primary oocyte

1. The primary oocytes are produced during the embryonic stage by oogenesis.
2. Each oocyte then gets surrounded by a granulosa cells layer called a primary follicle.
3. A large number of primary follicles degenerate during the phase from birth to adolescence stage.
4. The primary follicles get surrounded by more layers of granulosa cells, thereby forming secondary follicle.
5. The secondary follicle soon transforms into a tertiary follicle filled with a fluid called the antrum
6. At this stage, the primary oocyte completes the first meiotic division.
7. The primary oocyte completes the meiosis I to form a secondary oocyte and the first tiny polar body.
8. The tertiary follicle inside the secondary oocyte changes into a mature follicle called the Graafian follicle.
9. The secondary oocyte gets surrounded by zona pellucida.

Ovulation :

1. The release of the ovum from the ovary by the rupturing of the Graafian follicle is called ovulation.
2. When ovulation occurs then the cells of the Graafian follicle transform into a structure called corpus luteum.
3. This corpus luteum secretes a large amount of hormone called progesterone which is essential for the maintenance of the endometrial lining of the uterus and the implantation of the fertilized egg.