Men's testicles black

The reason why men have dark testicles in our lives is due to the structure of the scrotum itself. The scrotum is connected to the skin of the penis and the inner thigh. At this time, there are many capillaries on the skin and many elastic fibers in the connective tissue. Therefore, when men have dark testicles, it is a very normal physiological phenomenon. You can understand the causes of dark testicular skin.

The scrotum is like a thin and flexible leather bag, growing between the base of the penis and the perineum. When a person stands, it hangs there. It is connected to the pubic region, the skin of the penis, the skin of the inner thigh, and the skin of the perineum. From the outside, there is a longitudinal scrotal suture on its midline, which is a trace left by the embryonic development. The scrotal skin is soft and weak, smooth and elastic, with sparse and curly pubic hair. Under the skin is only a layer of fascia, which is mainly composed of smooth muscle, containing dense connective tissue and a lot of elastic fibers. The front and back walls of the tunica carnosus have fibers extending deep into the midline and connecting to each other to form a diaphragm, dividing the scrotum into two small left and right pockets, which contain the left and right testicles and epididymis respectively. The tunica carnosus is rich in blood vessels. There are also several layers of fascia and levator testis under the tunica carnosus, which are mainly composed of the aponeurosis of the abdominal wall muscles and the continuation of muscle fibers. There is also a spermatic cord in the scrotum, which is a round cord-like object composed of the vas deferens, testicular artery, venous plexus, many small blood vessels, nerve plexus, lymphatic vessels and capsule.

The support and covering of the scrotum, and the suspension of the spermatic cord and levator testis all play a mechanical protective role on the testicles. They can cushion the vibration of the testicles during walking and exercise, and are of certain significance in preventing trauma.

The scrotal skin is very sensitive to the outside temperature. It has no subcutaneous fat but abundant sweat glands, which helps to dissipate heat. When swimming, the water temperature is much lower than body temperature, which stimulates the smooth muscle of the fascia and the levator testis to contract and raise the position of the testicles. The scrotal skin shrinks into dense wrinkles and retracts to the perineum, preventing heat dissipation and helping to keep warm. The same phenomenon occurs when the weather is cold. On the contrary, when the outside temperature rises, the smooth muscle and levator testis relax, the testicles descend and leave the body, the scrotal skin relaxes, and the heat dissipation area is increased, which is conducive to local heat dissipation. In addition, the arteries in the spermatic cord are entangled with the parallel veins. The blood in the two vascular systems flows in opposite directions with only a thin blood vessel wall between them, forming a countercurrent exchange system. The veins continuously take away the heat from the arterial blood in the abdominal cavity. As a result, the blood temperature of the testicular artery can be 5~2°C lower than that of the abdominal aorta. The scrotum regulates the temperature of the scrotum and testicles through these mechanisms. You must not underestimate the ability of the scrotum, which is very important for human reproduction. Because temperature has a great influence on the spermatogenesis process of the testicles. The temperature inside the scrotum is about 2°C lower than that inside the body, which is the optimum temperature for spermatogenesis. If the temperature is too high, spermatogenesis will be hindered or even completely stopped, and the secretion of testosterone will also decrease. It is worth noting that any failure in the above links will affect the regulation of scrotal temperature and cause infertility. For example, there is too much scrotal fat, the testicles have not descended into the scrotum, varicose veins slow down the blood flow and cannot take away the heat in time, and the pants are too tight to affect air circulation and press the testicles tightly against the perineum. These situations are all specially introduced in this book.

As for the dark color of the scrotal skin, it is affected by sex hormones. Originally, a person's skin color depends on various pigments, especially the amount of melanin, the thickness of the skin, and the contraction or relaxation of blood vessels. The important factor affecting the melanin deposition of the skin is sex hormones. The concentration of sex hormones in the sex organs and other parts is high. As a result of long-term hormone stimulation, a large amount of melanin is deposited and the skin color becomes very dark, especially after wrinkles and thickening. Based on the same reason, you may have noticed that the color of the nipples and the surrounding areola of adult men is also quite dark! The sex hormone level of little boys is very low, so the skin color does not change much, and the scrotum is similar to the surrounding skin color. This change in pigmentation will only appear after entering puberty.

Expert Tips: After reading Why is a man's scrotum black? You now know why a man's scrotum is black! A man's scrotum is very fragile and must be taken care of on a regular basis, especially in the hot weather now, so pay more attention to cleaning!