INTRODUCTION The Prostate and Its Problems

The prostate is a gland located in the pelvic area directly beneath the bladder. It surrounds the urethra (the tube that conducts urine from the bladder to the penis). The prostate is both a gland and a muscle. As a gland it produces a milky, alkaline fluid that is mixed with sperm (produced in the testicles) to produce the fluid (semen) ejaculated during sexual intercourse and masturbation. The prostate gland also contains an enzyme, 5-alpha-reductase, which converts testosterone to dihydrotestosterone. As a muscle the prostate works to propel seminal fluid through the urethra and out of the penis during ejaculation. The muscle part of the prostate also acts as a “gate” for the flow of urine. There are two shut-off valves that control urination, one (internal sphincter) at the junction of the bladder and the upper part of the prostate, the other (external sphincter) at the base (apex) of the prostate. Both are required to prevent incontinence and dribbling. The upper shut-off valve also prevents seminal fluid from “shooting backwards” into the bladder during ejaculation (retrograde ejaculation).