The prostate gland is part of the male reproductive system. It is located in front of the rectum and under the bladder. It surrounds the urethra, the tube through which urine flows. A healthy prostate is about the size of a walnut.

 

The prostate contributes to the contents of semen (seminal fluid). During ejaculation, semen carries sperm out of the male body.

 

Male hormones, known as androgens, make the prostate grow. The testicles are the main source of male hormones, including testosterone. The adrenal gland also makes testosterone, but in small amounts.

 

If the prostate grows too large, it squeezes the urethra. This may slow or stop the flow of urine from the bladder to the penis.