Function of the prostate gland
The prostate is a gland in the male reproductive system that looks like a chestnut measuring approximately 3 centimetres high and 4 centimetres wide and weighing no more than 20 grams.
- It is located under the bladder, in front of the rectum and surrounds the top of the urethra, the canal that eliminates urine from the bladder.
- It plays a very important role in male fertility: it is involved in the formation and development of sperms. It also produces much of the ejaculated liquid, which is made up of sperms and prostate fluid.
- In addition to its sexual role, due to its location, the prostate gland also plays a role in ensuring that the micturition system is working well because it is closely linked to the two sphincter muscles that ensure good urinary retention.
Source : www.prostatecancercentre.ca
The prostate is divided into 3 zones:
- Peripheral zone: this is the largest zone of the prostate. Most of the malignant tumours associated with the prostate (approximately 75%) occur in the peripheral zone (INCa, www.e‐cancer.fr). It is the closest zone to the rectum and, therefore, easy for the doctor to feel when doing a rectal examination.
- Transition zone: this is the area at the centre of the prostate. The zone increases in size with age and soon becomes the largest part of the prostate. It is also known as a prostate adenoma (or benign prostatic hyperplasia = PBH) that occurs to almost all men over 70. Prostate tumours located in the transition zone are unreachable during a rectal examination by a doctor; they can only be detected following a biopsy.
- Central zone: this is the area around the ejaculatory ducts.
The prostate is a hormone-dependent gland, i.e., it evolves in relation to fluctuations in your hormone levels, since its growth and size rely on the excretion of testosterone, or more specifically, on dihydrotestosterone (DHT), a hormone produced when the enzyme, 5alpha‐reductase, synthesises testosterone contained in the prostate.
The amount of testosterone secreted varies over time: it rises during adolescence and reaches its peak at between 30 and 45, before decreasing progressively until it again reaches pre-adolescent levels after the age of 75. The prostate, on the other hand, never stops growing.
60% of men over age 60 have an enlarged prostate. This number rises to 70% at age 70 and 80% at age 80 (AFU, 2008).
With age, prostate enlargement tends to cause urinary troubles, such as frequent needs to urinate, weak urine stream, difficulty urinating, or sometimes a feeling of incomplete bladder emptying.
AFU, 2008, 4èmejournée de la prostate, 15 September 2008, press release.
INCa, www.e‐cancer.fr (http://www.e‐cancer.fr), Prostate cancer file.