taken from Small Gland, Big Problem 4th Edition
by Professor Roger Kirby, Health Press 2011
The prostate is a walnut-sized gland that is present only in men. It is located deep in the pelvis, at the exit of the bladder, and surrounds the tube known as the urethra (through which urine flows from the bladder to the outside of the body). Tiny at birth and throughout childhood, the prostate enlarges after puberty, stimulated by rising levels of the male hormone testosterone secreted by the testes, to a volume of around 20 mL. Although the prostate is small compared with other organs, it looms ever larger as a potential source of disease and disability once a man passes middle age.
The prostate is subdivided into three zones: central, transition and peripheral, which are shown in the diagram opposite. The peripheral zone is located at the back of the prostate and is the part most susceptible to both prostate cancer and prostatitis. The third and most common prostate problem – benign prostatic hyperplasia (BPH) – develops in the transition zone, which lies in the middle of the gland and surrounds the urethra.