It is a process that takes place in the testicles or gonads of males of a species where sperm or male sex cells are produced. This process is activated by the hormone GnRH that is produced in the hypothalamus, and the final maturation of the sperm occurs in the epididymis. It lasts between 62 and 75 days in the human species.
This process consists of two stages, meiosis or spermatocytogenesis and spermatogenesis, which is the structural formation of sperm. During the first phase, haploid cells are formed, that is, with half the genetic load of the individual. These cells become known as spermatids.
The spermatids go through a differentiation process in which the nucleus moves towards one of the poles of the cell and the centrosome gives rise to two centrioles. One of the centrioles is located near the nucleus forming a plate while the other gives rise to an axial filament or tail.
Oogenesis is female gametogenesis, it is the development and differentiation of the oocyte in animals through a meiotic division. Oogenesis begins in the prenatal stage and continues with the sexual maturation of women. Diploid germ cells generated by mitosis are known as oogonia and are found in the follicles of the ovary.
These grow and undergo modifications until they become primary oocytes; these go through a meiotic division and give rise to a secondary oocyte and a first polar body, then another meiotic division occurs and the secondary oocyte forms two cells, one larger and a second polar body.
The polar bodies disintegrate while the larger cell develops into a mature haploid egg cell. The ovules are found as part of the ovarian follicles. Its production is regulated by pituitary hormones: follicle-stimulating hormone and luteinizing hormone.
In the female fetus, oogonia are formed and the process of meiosis stops at the secondary oocyte stage until an oocyte is shed at puberty in each menstrual cycle. The second meiotic division will occur after sperm penetration.
Difference Between Spermatogenesis and Oogenesis
- During oogenesis, a greater amount of nutritive material accumulates.
- The resulting cells in oogenesis have different sizes because the nutritive material is not evenly distributed.
- The cells that result from spermatogenesis are of equal size.
- Oogenesis produces only one functional gamete.
- Spermatogenesis produces four functional gametes.
- Oogenesis begins in women in the third month of intrauterine development.
- Spermatogenesis begins in men when they reach puberty.
- Primary oocytes are retained in premeiosis until ovulation.
- The primary sperm continue their process of meiotic reproduction.