Figure 4-5
Anterior view of the male pelvic cavity.
Anterior view of the male pelvic cavity.
The male pelvic cavity contents are from anterior to posterior: the urinary bladder, located posterior to the pubic symphysis, and the rectum (Figure 4-5).
Remember, in the male, the urinary system and the reproductive system merge - the bladder empties immediately into the center of the prostate gland, the prostatic urethra. The ejaculatory ducts, a common duct from the ductus deferens and seminal vesicles, also empty into the prostatic urethra. The prostatic urethra continues as the penile urethra on its way to the exterior through the penis (Figure 4-6).
Returning to the primary male sex gland, the testes, let's investigate their position in the scrotum and their structural connection with the rest of the male uro-genital tract, as well as other abdominal structures.
During development the testes, anchored to the anterior abdominal wall by the gubernaculum, descend in the abdominal cavity. This is implemented by a difference in the growth rates between the gubernaculum and the rest of the body cavity. The testes pass through the abdominal wall via the inguinal canal. They push all layers of the abdomen ahead of them until they come to rest in the anterior abdominal wall pouch called the scrotum.
Throughout their descent, the testes have dragged along their life-line, the testicular artery, vein and nerve. They have also brought along the ductus deferens, which carries testicular products (sperm) away from the testes toward their eventual confluence with the urinary system.
This ad-mixture of vessels, nerves, a glandular duct and lymph vessels is known as the spermatic cord. The spermatic cord is really formed in the inguinal canal as the testicular vessels and ductus deferens join each other at the deep inguinal ring. The spermatic cord does not exist inside the abdomen.
Once through the superficial inguinal ring and outside the abdomen, the spermatic cord includes all the tubular structures above. It also includes all layers of the abdominal wall that have been pushed ahead of the descending testicles.
The testes are capable of producing virtually unlimited amounts of sperm cells. The ducts of the testes merge and form the epididymis, where immature sperm cells gather and mature into fertile sperm cells.
The emission and ejaculation process expells the sperm cells from the epididymis through a tubular duct system which carries them from outside the body wall into the pelvic cavity then back outside through the urethra of the penis. (Figure 4-6).
The tubular duct system from the epididymis to the ejaculaltory duct is the ductus deferens, more commonly known as the vas deferens. It passes through the inguinal canal into the interior of the pelvis and ends where it joins the ducts of the seminal vesicles to form the ejaculatory duct. The ejaculatory duct then empties into the prostatic urethra.
The seminal vesicles and the prostate both contribute to the formation of seminal fluid. When seminal fluid combines with sperm cells, the resulting mixture is called semen. During the male orgasm ejaculation occurs. Sperm cells mixed with seminal fluid are ejected through the tubular system and urethra by muscular contractions, exiting through the penis.