What are the testicles and what they are for: their main functions
The testicles are the male gonads, of great importance in man, because they are the producing devices of sperm and sex hormones, itself of testosterone.
They are glandular organs, a very important part of the male reproductive system. There are two, and they are in the perineal region, behind the base of the penis, inside the scrotal sac. They are covered by a set of covers in the form of a bag, called scrotum, which helps keep them at 1.3 degrees centigrade below body temperature.
Precisely, of not having this temperature difference with respect to the body, the sperm could not mature and the man would have fertility problems (for that reason the high temperatures can cause infertility in some men, especially in the case of varicocele, by the use of tight pants or underwear ...).
The scrotum has no fat and its muscles react to heat, thus extending and contracting your skin, depending on whether you are in a hot or cold environment, it also has a temperature regulation mechanism dependent on the arterial system, which provides heat , and the venous system, which reduces the temperature.
As we indicated, the normal number of testicles in an individual is two, one on the right side and one on the left side, abnormally it may be the case that an individual has only one testicle by absence of the development of the other, this is He calls it monorchidism, when both testes are missing it is called anorchia.
The size of the testicles in adults reaches between 4 and 6 centimeters in length and between 2 and 4 cm in width. This size remains constant for almost the entire life of the individual, except in old age where you can perceive a slight atrophy, or a slight increase in size due to the consumption of steroids.
The vascularization of the testicles is given by the arteries, veins and lymphatic vessels, the testicles are irrigated by the spermatic arteries, the deferential artery and the funicular artery, as for the veins, the spermatic veins are in charge of the blood drainage.
Layers that protect the testicles
The testicles are surrounded by 7 layers that from surface to depth are:
- The scrotum: which is the surrounding skin of the rest of testicular structures. It usually has hair with deep hair follicles and abundant sebaceous glands.
- The dartos: a thin muscle attached to the scrotum.
- A subcutaneous cell layer
- The external spermatic fascia.
- The cremaster: which is a muscle that is in the crease of the groin and testicular bags.
- The internal spermatic fascia.
- The tunic of the testicle.
The structure of the testicle is given by different parts, these are being:
- The albuginea: It is a fibrous layer of white, dense and elastic connective tissue that surrounds the testicle and the epididymis.
- Seminiferous ducts: they are the ducts that produce the sperm, they are inside some lobes that have formed the testicular septa, which start from the tunica albuginea and join in the mediastinum testis.
- Excretory ducts of sperm: the semen leaving the aforementioned seminiferous canals pass through the testicular network, which consists of three parts, the septal rete, the mediastinal rete and the extra testicular rete, then passes through the efferent conduits, which communicate the rete testis with the epididymis.
- Epididymis: is the narrow and elongated tube, located in the upper posterior part of the testicles, connects the vas deferens to the back of each testicle. It is constituted by the meeting and apelotonamiento of the seminíferos conduits.
Functions of the testicles
The main function of the testes is to produce sperm. But it is not its only important function. As well produces hormones called androgens, among which is the testosterone.
The spermatogenesis process is carried out to produce the spermatozoa. It needs, apart from the germ cells, the Sertoli cells, which constitute a support.
The testicle begins to be hormonally active from the eighth week of gestation. The Sertoli cells produce a substance that inhibits Muller's ducts when under the action of the hormone FSH.
Said inhibitory substance is able to induce the regression of the ducts mentioned above, has action in the abdominal phase of the descent of the testicle and also produces an increase of androgenic receptors on the surface of Leydig cells.