Its size and volume vary with age, and from one individual to the next. Situated below the bladder and in front of the rectum, the prostate gland surrounds the top part of the urethra (the canal that takes the urine from the bladder to the outside of the body).
All around the urethra, a set of muscle fibers are grouped at the bladder neck* and beneath the prostate, forming the urinary sphincter,* which releases to allow urine to pass and then contracts to ensure urinary continence. Contrary to popular belief, the prostate is not directly involved in erection mechanisms.
By contrast, the prostate is involved in the ejaculation mechanism and secretes part of the seminal fluid which serves as a means of transport and activation of the spermatozoa.