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A virtual section through the body showing the prostate and surrounding structures |
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The prostate is the shape and size of a walnut and is located low down in the pelvis, at the base of the bladder. It starts life as a tiny gland, whose growth and development during infant life are influenced by the principal male hormone, testosterone, and a number of other hormones produced by the pituitary gland. The pituitary, which sits in the centre of the brain, is the main hormone-producing organ of the body – growth hormone, prolactins (which in women help the manufacture of milk) and to a lesser extent thyroid hormones are all important in the growth of the prostate gland.
In adolescence the gland enlarges further, while growth occurring within the prostate itself leads to the development of microscopic glands which produce the prostatic secretion called prostate specific antigen (PSA). This fluid, which is rich in sugar and enzymes, has an important role to play in sexual activity. Sperm produced in the testicles drains through a series of tubes called the epididymis, then along the inguinal canal before passing deep into the pelvis to meet the prostate. Here PSA, which drains from the prostatic glands along a collection of tiny tubes (prostatic ducts), is released into the sperm at the moment of orgasm. The sperm is nourished by this sugar-rich fluid and kept alive for its journey into the outside world.
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Detailed section through the body showing the prostate |
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The main function of PSA is to clear away the residual matter left within the prostatic ducts after orgasm – if left alone, this debris would solidify and block them. The action by which the enzymes in PSA dissolve and remove this debris is termed ‘protease activity’. In other words, the enzymatic activity of PSA keeps the system clean. The level of PSA normally present in the bloodstream reflects the activity and health of the prostate gland. This can be measured by a PSA test.
Prostate growth continues with the years, and enlargement of the gland may be such that it can cause significant difficulties. In particular, the gland’s physical location may lead to problems with urination. When you urinate, urine flows from the bladder along a tube called the urethra, which passes through the centre of the prostate before leaving the body via the penis. The flow of urine is controlled by valves, which are opened and closed at will on urination. However, the neck of the bladder may be obstructed by a large prostate, causing difficulty in urine flow.
