The prostate gland

The prostate gland is only found in men. It’s about the size of a walnut and gets a little bigger with age. It surrounds the first part of the tube (urethra) that carries urine from the bladder along the penis.

Male reproductive organs
Male reproductive organs

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The prostate produces a thick, white fluid called semen, which mixes with the sperm made by the testicles. The mixture of sperm and semen is sometimes known as the ejaculate. The prostate also produces a protein called prostate specific antigen (PSA). This turns the semen into liquid. A small amount of PSA naturally leaks into the blood.

Larger amounts of PSA leak into the blood if the prostate gland is enlarged, inflamed or infected, or if there’s cancer in the gland.

The growth of prostate cells and the way the prostate gland works is dependent on the male sex hormone testosterone, which is produced in the testicles.

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What is the PSA test?

The prostate specific antigen (PSA) test is a blood test that measures levels of PSA protein in the blood.