Sperm Production & Maturation

Males continuously produce new sperm in the seminiferous tubules located inside his testicles from puberty until death.

The newly produced sperm leave the testicle and enter one of the epididymis (a curved structure about one-half inch long located on the back side of each testicle). Inside each epididymis is a thin, tightly coiled tube (about 20 feet long!) where, as the sperm move through, they begin a maturation process which gives them the ability to swim.

The sperm then enter one of the vas deferens. Each tube is about 20 inches long which leads from one testicle into the body, loops around the bladder, and comes back down toward the inside end of the urethra.

From production to maturation takes about 70 days.

After it travels through the vas deferens the sperm sits and waits to come out in ejaculation.

Each vas deferens joins with the opening of a seminal vesicle. Seminal vesicles produce a fluid which will protect the sperm from vaginal secretions and which will provide nutrition for the sperm.

Another place sperm-protecting fluid is produced is in the prostate gland. The prostate gland plays an important part in male sexual arousal (when a penis, finger, or other object is inserted into a man's anus the object pushes against the prostate causing a pleasurable feeling).

Further down the urethra are the Cowper's Glands, which produce a mucus-like fluid during sexual arousal. This fluid lubricates the urethra. This can happen close to the time of actual ejaculation, so sperm may already be present in the pre-ejaculatory fluid. The presence of sperm means that pregnancy can occur if pre-ejaculatory fluid gets into the vagina.

At ejaculation, sperm, fluid from the seminal vesicles and fluid from the prostate gland mix together as semen and enter the urethra to be forced out of the opening in the head of the penis by the muscle spasms of orgasm.

The total amount of semen ejaculated is usually around one teaspoon, which contains 120 to 600 million sperm (someone actually counted!).

This teaspoon contains 1/3 fluid from prostate, 2/3 fluid from seminal vesicles, and a very microscopic volume of sperm. This is why when a man has a vasectomy the volume of semen ejaculated doesn't decrease since only the sperm are missing.

The colour of semen varies, normally shades of white, yellow or gray. The texture is usually creamy, sticky, and thick immediately after ejaculation. The semen then becomes more liquid but eventually dries after exposure to air.

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