Scrotum Function and Anatomy
A part of the male reproductive system, scrotum is a thin sac of skin that contains testes, epididymis, and spermatic cords. Divided into two compartments, the dual-chambered protuberance of muscle and skin is an extension of the perineum located between the anus and penis. Each compartment comprises:
- one of the two testes that produce sperm
- one of the epididymis that store sperm
The two channels are divided by a middle ridge, known as the raphe that connects the septum, which is a form of muscular partition. The scrotum is an extension of the skin of lower abdomen located immediately behind the penis. The pigmented and wrinkled thin layer of skin or the scrotal wall is lined with smooth muscle tissue and has many sweat and oil-producing glands and some hair.
The anterior and posterior scrotal arteries are responsible for supplying blood to the scrotum, which has an abundant supply of nerves.
Tunica vaginalis is located within the external, cremasteric, and internal spermatic fasciae that cover the lateral, medial, and anterior surfaces of each testis.
The key function of scrotum is to maintain the temperature of testes to almost 1–8° below the normal body temperature. Protruding from the body wall, the scrotum contracts from sexual stimulation, exercise, or cold and expands when warm. The contracted scrotum conserves heat, and a relaxed scrotum permits the air circulation that affects cooling.
All in all, the scrotum is the body’s way of controlling the testes temperature.
Temperature control to protect sperm
Primarily, the function of the scrotum is to control the climate of testes in order to maintain the desired temperature for sperm. It is important that the testes temperature is slightly lower than that of the rest of the body. Any increase in scrotum temperature may affect the sperm count, causing it to go down.
The scrotum maintains the temperature of testes by altering the distance between the abdomen and testicles. Any rise in the room temperature could cause the scrotum to move testes away from the abdomen, increasing the amount of the exposed surface area and helping dissipation of excess heat.
Scrotum is also responsible to protect the testes and allowing the sperm adequate time for maturing before being discharged. Some biologists believe that the positioning of the testes in the scrotum ensures that sperm gets sufficient time to mature, claiming that any different positioning of the scrotum instead of their actual position could cause regular changes in terms of abdominal pressure due to the contraction and relaxation of abdominal muscles. In that case, testes would empty quicker than they actually do, leaving little time for the sperm to fully mature.