Question

How long does the process of oogenesis take place in humans? Does it complete in intrauterine life or continue till the age of 50?

Answer 1

Oogenesis in humans:

1. Oogenesis is the process by which female gametes are formed.
2. Only 12 days are required for oogenesis, hence the nurse cells are metabolically quite active during this time.
3. It is completed in the intrauterine line which is between conception and birth.
4. The ovary goes through a process called oogenesis.
5. One mature egg is produced by oogenesis from one initial oocyte; in humans, this happens around once every four weeks.

Steps involved in Oogenesis:

Prenatal stage:

1. The primary oocyte grows while being arrested at meiosis-I.
2. They proliferate and differentiate into a stratified cuboidal epithelium.
3. Granulosa are these types of cells.
4. To form the zone pellucid, these cells secrete glycoproteins around the primary oocyte.

Antral stage:

1. The fluid-filled spaces between the granulosa of the antral stage
2. Cells join together to form the antrum, a central fluid-filled space.
3. These are known as secondary follicles.
4. During each monthly cycle, secondary follicles develop under the influence of follicle-stimulating hormone and luteinizing hormone.

Pre-Ovulatory Stage:

1. The LH surge causes this stage, and meiosis-I occurs here. Inside the follicle, two haploid cells of unequal size form.
2. One of the daughter cells that receive less cytoplasm is formed by a polar body.
3. This Cell does not participate in the development of an ovum.
4. The other daughter Cell is the secondary oocyte.
5. Meiosis-II takes place in the two daughter cells.
6. The polar body replicates to form two polar bodies, whereas the secondary oocyte is arrested in meiosis-II metaphase.