Category B - full version without watermark 720x576 (check terms and conditions at www.teledesign.de) The version with watermark is for free to embed The prostate gland: where is it situated? How large is it on average? What are its functions? The prostate of the man reaches its full size only at the age of about 20. It resembles a chestnut and weighs about 20 grams. It lies in between the bladder and the pelvic floor. Below the urinary bladder it surrounds the urethra. The prostate consists of muscle- and connective tissue fibers. In between these fibers there are many glandular tubes. The prostate can be divided into an inner and an outer part of the gland. Its most important function is the production of a fluid -- a secretion -- without which the sperms could not live nor move. Growth, development and function of the male reproductive organs, which include also the prostate, are determined by the male sex hormones. The most important male sex hormone is testosterone. Controlled by the interbrain and the pituitary gland, above all the testicles produce this hormone. Testosterone production increases with the entrance into puberty. This is paralleled by changes in structure and growth of the prostate. Accordingly testosterone also plays a central role for diseases of the prostate. For example the benign enlargement: around the age of 30 there is a growth spurt of the prostate gland. It will only grow -- however -- if enough of a certain hormone is available. The so called di-hydro-testosterone. It is produced within the prostate from the male sexual hormone testosterone. The conversion is effectuated by a special protein: the enzyme 5-alpha-reductase. The effect: cell growth in the prostate. The beginning of the benign enlargement.