Detailed Anatomy of the Male Reproductive System (Part 1): The Mysteries of Scrotal Temperature Control, Testicular Spermatogenesis, and the Twisted Path of the Vas Deferens

The male reproductive system includes the following organs: scrotum, testes, epididymis, vas deferens, seminal vesicles, ejaculatory ducts, prostate, and penis. The testes are enclosed within the scrotum. The scrotum and penis are the parts exposed outside the body, called the external genitalia; the remaining organs are located in the lower abdomen and are called the internal genitalia. A brief introduction to each is as follows: 1. Scrotum: The scrotum is located behind the penis and in front of the anus. It is a sac made of skin. The skin is brown, thin, and soft, with many wrinkles. The subcutaneous tissue contains a large number of smooth muscle fibers called the dartos fascia. The dartos fascia forms the scrotal septum along the midline, separating the testes and epididymis on both sides. The dartos fascia contracts when cold and expands when warm, thereby regulating the temperature inside the scrotum, which is conducive to sperm production and survival. When the muscles contract, the scrotum naturally contracts and shrinks, deepening the wrinkles. The scrotal cavity is divided into two parts, left and right, each containing a smooth membrane that encloses the testes and epididymis.