BPH, or an enlarged prostate, is a condition that will affect most men as they get older. It is not prostate cancer, and does not raise your risk of prostate cancer.
Prostate Cancer Foundation - About the Prostate
Interactive prostate anatomy - 3D Rotation
The prostate is a gland about the size and shape of a walnut. It is located in front of the rectum, just below the bladder. The urethra – the tube that carries urine out of the body – passes through the centre of the prostate, and is surrounded by its spongy tissue.
The prostate is a gland which produces a milky-white fluid. This is called the prostatic fluid. It combines with sperm from the testis, and fluid from the seminal vesicles to form semen. Prostatic fluid comprises approximately 20-30% of the volume of ejaculatory fluid. It's function is to provide nutrients to sperm, and aid in sperm delivery.
The urethra passes from the base of the bladder through the prostate and out through the penis. The portion of the urethra that is located within the prostate is called the "prostatic urethra." In the prostate there are muscular fibers surrounding the prostatic urethra which contract to control the flow of urine.
The prostate sits directly on top of the muscles of the pelvic floor. Some of these muscles form the external urinary sphincter. This muscle plays an important role in urinary continence.
A network of nerves is located on either side of the prostate. This network contains nerve fibres which are responsible for erection.