Prostate gland
The prostate is a gland that is part of a man's sex organs. Its main function is to secrete and store a clear, slightly acidic fluid that is part of semen.
A healthy prostate is approximately the size of a walnut. It surrounds the urethra just below the urinary bladder. It is located in front of the rectum and part of it can be felt during a rectal exam.
The male urethra has two functions: to carry urine from the bladder during urination and to carry semen during ejaculation. Within the prostate, the urethra coming from the bladder merges with the two ejaculatory ducts.
Semen is composed of sperm and seminal fluid; about 10-30% of the seminal fluid is produced by the prostate gland, the rest is produced by the two seminal vesicles.
The prostate also contains some smooth muscle tissue which helps to expel semen during ejaculation.
To work properly, the prostate needs male hormones (androgens). Male hormones are responsible for male sex characteristics. The main male hormone is testosterone, which is produced mainly by the testicles. Some male hormones are produced in small amounts by the adrenal glands.
Prostate glands are found only in males; Skene's glands in females are homologous to the prostate gland in males.
Disorders of the prostate
Inflammation of the prostate gland is known as prostatitis. If the prostate grows too large it may constrict the urethra and impede the flow of urine, making urination difficult and painful and in extreme cases completely impossible. Prostatitis is treated with antibiotics, prostate massage or surgery.
In older men, the prostate often enlarges to the point where urination becomes difficult. This is known as benign prostatic hyperplasia and
can be treated with medication or with surgery that removes part of the prostate. This type of surgery is nowadays usually performed with a long instrument through the urethra, without the need for an external incision.
Prostate cancer is one of the most common cancers affecting elderly men in developed countries and a major cause of death. Regular rectal exams are recommended for elderly men to detect prostate cancer early. There is also a blood test measuring a certain protein associated with prostate cancer. The cancer is treated with radiation and/or surgery.
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