THE PENIS

MALE EXTERNAL GENITALIA:
PENIS AND SCROTUM

Penis

• (A) Circumcised
• (B) Uncircumcised
• (C) Erect


The penis (shaft) and scrotum (balls) are the external sexual organs of men.

Glans

The glans is clearly visible in illustration (A) as the head of the penis. The glans is usually covered by the prepuce unless the penis is erect, except in circumsized men, whose foreskin has been surgically removed. The glans is highly sensitive, as is the corona that connects the glans to the shaft of the penis.

Corona

The 'crown,' a ridge of flesh demarcating where the head of the penis and the shaft join.

Frenulum, Frenum

A thin strip of flesh on the underside of the penis that connects the shaft to the head.

Foreskin, Prepuce

A roll of skin which covers the head of the penis. It is rich in nerve endings. Surgical excision (removal) of the foreskin of men is called circumcision.

Urethra, Meatus

The opening at the tip of the penis to allow the passage of both urine and semen.

Smegma

A substance with the texture of cheese secreted by glands on each side of the frenulum in uncircumsized men.

Scrotum

The scrotum is a sac that hangs behind and below the penis, and contains the testes (testicles), the male sexual glands. The scrotum's primary function is to maintain the testes at approximately 34 C, the temperature at which the testes most effectively produce sperm.

The male sexual glands, the two testes within the scrotum produce sperm and testosterone. Within each testis is a kilometer of ducts called the seminiferous tubules, the organs which generate sperm. Each testicle produces nearly 150 million sperm every 24 hours.

Epididymis

The epididymis is a 'holding pen' where sperm produced by the seminiferous tubules mature. The sperm wait here until ejaculation or nocturnal emission.

Vas Deferens

The ducts leading from the epididymis to the seminal vesicles. These are the ducts that are cut during the procedure known as vasectomy.

Seminal Vesicles

The seminal vesicles produce semen, a fluid that activates and protects the sperm after it has left the penis during ejaculation

Prostate Gland

Also produces a fluid that makes up the semen. The prostate gland also squeezes shut the urethral duct to the bladder, thus preventing urine from mixing with the semen and disturbing the pH balance required by sperm.

Corpa Cavernosa

The corpora cavernosa are the two spongy bodies of erectile tissue on either side of the penis which become engorged with blood from arteries in the penis, thus causing erection.

Ejaculatory Ducts

The path through the seminal glands which semen travels during ejaculation.

Cowper's Glands

The Cowper's glands secrete a small amount of pre-ejaculate fluid prior to orgasm. This fluid neutralizes the acidity within the urethra itself.