The prostate is a muscular, walnut-sized gland that surrounds part of the urethra, the tube that transports urine and sperm out of the body. (A gland is a group of cells that secretes chemicals that act on or control the activity of other cells or organs.)
The main function of the prostate is to produce semen, the milky fluid that transports sperm. Sperm is produced in the testicles, which also produce the main male hormone testosterone. Testosterone stimulates the growth and function of the prostate during puberty, as well as the production of prostatic fluid for semen.
During sexual climax (orgasm), the muscles of the prostate contract to push the semen through the urethra and out through the penis. The urethra also carries urine, a waste product made by the kidneys and stored in the bladder. When the penis is erect during sexual intercourse, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm.
Where is the prostate located?
The prostate is located directly beneath the bladder and in front of the rectum. Because the upper portion of the urethra passes through the prostate, if the gland becomes enlarged it can obstruct the passage of urine or semen through the urethra.
