Is the skin of scrotum very black and wrinkled? What is the functional structure of scrotum
The scrotum is like a thin and tough skin pocket on the wall. It grows between the root of the penis and the perineum. When standing, it hangs there and connects with the pubic bone, the skin of the penis, the skin of the inner thigh and the skin of the perineum. From the appearance, there is a longitudinal scrotal suture in the middle line, which is the mark left during embryonic development. The scrotal skin is soft, weak, smooth and elastic, with thin curly pubic hair on it.
There is only a layer of sarcolemma under the skin, mainly composed of smooth muscles, including dense connective tissue and many elastic fibers. The anterior and posterior walls of the membrane extend to the deep layer in the middle of the midline and connect with each other to form a membrane. The scrotum is divided into two small pockets on the left and right, which are respectively installed with the left and right testicles and testicles. The blood vessels flowing through the sarcolemma are abundant. There are several layers of fascia and testicular muscle under the sarcolemma, mainly composed of the abdominal wall tendon and muscle fibers. There is spermatic cord in the scrotum, which is a round cord-like substance composed of vas deferens, racemose venous plexus, lymphatic vessel, capsule, nerve plexus, many small vessels, testicular artery, etc.
The support and wrapping of the scrotum, the suspension of the spermatic cord and the spermary muscle play a mechanical role in protecting the spermary, and buffer the vibration of the spermary during walking and exercise, which has certain significance in preventing trauma.
Why is the scrotum black and wrinkled?
The scrotal skin is sensitive to the external temperature. There is no subcutaneous fat and rich sweat glands, which is helpful for heat dissipation. When swimming, the water temperature is lower than the body temperature, which stimulates the smooth muscle of the sarcolemma and the contraction of the testicular muscle, improves the position of the testicles, and the scrotal skin tightens and folds, and returns to the perineum to prevent heat dissipation, which helps to keep warm. The same phenomenon occurs when the weather is cold.
On the contrary, when the external temperature increases, the muscles are smooth, the testicles relax, the testicles drop, the body falls off, the scrotal skin relaxes, and the heat dissipation area increases, which is conducive to local heat dissipation.
In addition, the arteries in the spermatic cord are wrapped in bundles of parallel veins. The blood in the two sets of vascular systems only flows in reverse across the thin vascular wall, forming a countercurrent exchange system. The venous blood constantly carries away the heat from the arterial blood in the abdominal cavity. The blood temperature of the testicular artery is 5~2 ° C lower than that of the abdominal aorta.
The scrotum regulates the temperature in the scrotum and testis through these mechanisms. Don't underestimate the ability of the scrotum. That is important for human reproduction. Because temperature has a great influence on the spermatogenesis process of testicles. The temperature in the scrotum is about 2 ° C lower than that in the machine body, which is the best temperature for spermatogenesis. If the temperature is too high, the spermatogenesis will be blocked. At the same time, the secretion of testosterone will also be reduced. It is worth noting that the failure of any of the above links will affect the regulation of the scrotal temperature and lead to infertility. When there is too much scrotal fat, the testicles do not fall into the scrotum, varicose veins slow down the blood flow, can not immediately carry heat, tight pants affect the air circulation, press the testicles on the perineum, etc. This book has special introduction.