The prostate gland is a small gland that lies beneath the urinary bladder and in front of the rectum in males. The gland surrounds the top end of the urethra which carries urine from the bladder out of the body via the penis. The gland's size may vary with age. It is around the size of a walnut in younger men but usually increases in size as a man ages.
The prostate produces a thick, milky fluid that mixes with sperm to produce semen, the medium that carries sperm. The prostate produces a special protein called prostate-specific antigen (PSA), which helps to liquefy the semen. This prostatic fluid also protects and nourishes the sperm. The urethra passes through the centre of the prostate gland and carries the semen as well as the urine out of the body.
Diseases and disorders of the prostate gland
The prostate gland can be affected by several diseases and conditions and one of the most important of these is benign prostatic hyperplasia (BHP), a non-cancerous enlargement of the prostate. This is one of the most common conditions to affect aging males. Other conditions that affect the prostate include inflammation of the prostate gland or prostatitis and prostate cancer.
The development of the prostate starts before birth but its growth is stimulated by an increase in male hormones called androgens during puberty. So long as these hormones are present, the prostate stays roughly the same size in adults. The most important androgen in prostate growth is testosterone, which is made in the testes. This testosterone is converted to dihydrotestosterone (DHT) by an enzyme called 5-alpha reductase and DHT signals the prostate's growth and development.
Reviewed by Sally Robertson, BSc