Gonads is the name that describes the sex glands responsible for the course of an important function in the reproductive process of humans and other animals. Gonads produce reproductive cells, in turn called gametes, which are cells involved in the fertilization process. Gonads are found in almost all species of animals in the same specific number – in pairs. An exception may be made for some species of birds and invertebrates in which there is only one gonad. In the case of women, these are the ovaries, and in the case of men, the testes. Moreover, the possibility of the occurrence of zwitterionic gonads or both male and female gonads within one organism is distinguished. Both of these situations, however, are extremely rare.
The female gonad
The female gonad is located within the peritoneal cavity, near the side walls of the pelvis and the ligaments of the uterus. The ovaries are “attached” to the uterus with appropriate mesentery. The upper poles of the ovaries, on the other hand, include the fallopian tubes.
The ovaries are a relatively small organ, their volume can be estimated at about 6-8 ml. The ovaries are primarily used for reproductive purposes by producing and transporting eggs. In addition, they secrete female sex hormones, which include:
- estrogens,
- progesterone,
- relaxing,
- androgeny,
- inhibiny,
- hormone antimullerowski.
In addition to hormones, the ovaries also produce other substances that act endocrinologically.
Within the ovaries, there are ovarian follicles. During reproductive maturity (from the first menstruation to the onset of menopausal symptoms), the ovary regularly matures the Graaf follicle, in which the egg is located. The maturation of the Graaf follicle occurs under the influence of the follicle-stimulating hormone. When the follicle is mature, it ruptures. As a result, the egg is released and moves from the ovary to the fallopian tube. A red body is formed from a ruptured bubble, which then transforms into a yellow body. It plays an important role as it secretes progesterone, which enables the implantation of a fertilized egg in the lining of the womb.
Men’s gonad
Male gonads are testicles located in the scrotum. In most animal species, the testes are located outside the body. This is due to the course of the spermatogenesis process, which occurs efficiently at body temperatures below 37 degrees. For this reason, the scrotum is the “coolest” place in a man’s body, which allows for the proper production of sperm. The appearance of the scrotum is not symmetrical – most often the testicles are not evenly arranged, which may result from both the structure of the scrotum and slight differences between the size and weight of the testicles. The testicles have a slightly larger volume than their female counterpart – they range from 12 to 30 ml.
Male gonads are composed of a large number of interconnected tubules in which sperm-forming cells are located. Wires emerge from the testicles through which new cells enter the epididymis, where they mature into their proper form. From them, they pass into the vas deferens and then into the ejaculatory tract, which connects with the urethra.
The male gonads produce:
- testosterone,
- hormone antimullerowski,
- activins,
- inhibiny.
Gonadal sex
Based on the presence of specific gonads, it is possible to determine the gonadal sex of a specific representative of a given animal species. This koela translates into genital sex, that is, sexual differentiation based on the presence of specific external organs. The direction of the development of the gonadal sex is determined by the Y chromosome, responsible for the chromosomal sex.
Gonadal sex develops around the 6th week of pregnancy. Before this stage of fetal life, in both male and female embryos, the gonadal sex is identical. Under the influence of the Y chromosome, the gonad begins to transform into the nucleus, and in its absence, the gonads independently shape their tissues, slowly forming the ovaries. Under the influence of the development of gonads, the production of certain hormones also begins, which in turn affect the future development of the body. They are responsible, inter alia, for the development of the appearance features typical of boys or girls.
In extremely rare cases, the gonadal sex may be disturbed. Such a situation occurs quite rarely among people – on average, it affects one person in 20 thousand children born. A disorder of the gonadal sex may be related to either their abnormal development, their absence, or the presence of gonads of both sexes in one individual. The consequence of this condition may be the presence of external reproductive organs of both sexes in one person and possible disorders in the identification of one’s own gender identity.
When both the ovary and testes are present, the person’s gonadal sex is defined as bisexual. Such a situation may occur when there is an ovary on one side, while its pair is formed by a testicle located on the other side. When the gonad adopts the structures of both – the nucleus and the ovary – then we are talking about zwitterionic gonads.