What is the prostate gland?

The prostate gland is a male sex gland. It needs male hormones, primarily testosterone, to function. It is about the size of a walnut and is located in front of the rectum, behind the base of the penis and directly under the bladder. It is found only in men, and its function is to produce a thick fluid that is part of semen, that helps protect and nourish sperm cells and enables sperm to be released during ejaculation. The prostate surrounds the upper part of the urethra, the tube that empties urine from the bladder. Nerves involved in causing an erection of the penis are located adjacent to the prostate. This makes men who undergo prostate treatment susceptible to erectile problems, or impotence, as a result of damage to these nerves.