Name: Male Sex Hormones
Uploaded: 2019-07-19
Duration: 4 min 59 s
Description: The onset of puberty marks many changes. Have you ever wondered what brings these changes in the body? This video will help us understand the role of sex hor...

Question

Describe the process of oogenesis with a suitable diagram.

Accepted Answer

Oogenesis is the process of the formation of haploid female gametes. The initial steps in oogenesis up to the production of primary oocytes occur before birth in the female foetus. Oogenesis occurs in the outermost parts of the ovaries. It starts with a germ cell called oogonium, which undergoes mitosis to increase in number. The process of oogenesis takes place in three stages which are described below.

Prenatal stage: In this stage, the primary oocyte grows while being arrested in meiosis-I. The follicular cells proliferate, forming a stratified cuboidal epithelium. Such follicular cells are called granulosa cells, which secrete glycoproteins to form zona pellucida around the primary oocyte.

Antral stage: The characteristic of this stage is the presence of antrum, a central fluid-filled space formed by combining fluid-filled areas present between granulosa cells. These structures having central fluid-filled space are called secondary follicles. Every month, these secondary follicles develop under the influence of follicle-stimulating hormone and luteinizing hormone secreted from the anterior pituitary gland.

Pre-Ovulatory Stage: This stage is induced by the surge of luteinizing hormone, which causes the completion of meiosis-I. In this stage, two haploid cells of unequal sizes are formed within the follicle, from which one of the daughter cells that receive less cytoplasm forms a polar body. The polar body does not participate in oogenesis. The other daughter cells are known as the secondary oocyte. The daughter cells undergo meiosis-II, in which the polar body replicates to form two polar bodies, while the secondary oocyte arrests in the metaphase stage of meiosis-II.

Figure: OOGENESIS

Describe the process of oogenesis with a suitable diagram.

Important Questions on Human Reproduction

Learn and Prepare for any exam you want !