An organism undergoes a series of changes throughout its life cycle. Gametogenesis (spermatogenesis and oogenesis), play a crucial role in humans to support the continuance of generations.
Gametogenesis is the process of division of haploid or diploid cells to produce new haploid cells. In male and female human, there are two different types of gametes (reproductive cells)are present. Male gamete called sperm and female gamete called ovum.
In humans, two types of gametogenesis take place:
- Spermatogenesis: Sperm formation
- Oogenesis: Ovum formation
In male immature germ cells are produced from the testis. At puberty of male, this immature germ cell is converted into mature cells. Those mature cells are called as sperms. This process in the male is known as spermatogenesis. Spermatogonia are diploid cells which can undergo mitotic division. Primary spermatogonium undergoes meiosis and produces haploid cells- secondary spermatocytes. These secondary spermatocytes undergo the secondary meiotic division to produce immature sperms. At the stage of puberty, these immature cells are converted into mature sperms. This process is called Spermatogenesis. Hormones are involved in stimulating the spermatogenesis.
In females, the immature ovum is converted into the mature ovum. This process is called oogenesis. In the female ovary, millions of mother cells are formed during the fetal development. These mother cells undergo the meiotic cell division and lead to the production of primary oocytes. Primary oocytes are embedded with primary follicles on the outer layer. Primary follicles are bounded with more granulosa cell layer and form secondary follicles. Secondary follicles then turn into the tertiary follicle. At the stage of female puberty, tertiary follicles undergo some structural and functional changes and produce mature Graafian follicle. Ovum is released from the Graafian follicle during the menstrual cycle. The release of an ovum from the Graafian follicle is called as ovulation. Ovulation is controlled by the female reproductive hormone which is stimulated by the pituitary gland.
We have thus seen the basic introduction and common process involved in gametogenesis. For the complete understanding and illustrations of the topic, visit BYJU’S.