Having a kiwifruit size (or slightly larger than a walnut) and weighs approximately 20 grams, the prostate gland is a part of
the male reproductive system, located below the bladder, in front of the rectum and surrounded by the pelvic
muscles. The prostate also surrounds the urethra, a muscular tube that connects the urinary bladder to the
external sex organs to carry semen as well as urine out of the body.
The prostate gland
consists of about 4 zones (also called lobes): Anterior
fibro-muscular zone (or stroma), peripheral zone, central zone, and transition zone. Each zone has its main role
physiologically, pathologically and diagnostically. The anterior
fibro-muscular zone is made up mostly of muscle and fibrous tissue, and represents about 5% of the
prostate gland. The peripheral zone is the main target during rectal exam because the physician can feel it
by inserting a finger in the rectum; it represents up to 70% of the prostate size and the original site of
more than 70% of prostatic cancerss. The transition zone is the main site where enlarged prostate (benign
prostatic hyperplasia or simply BPH) develops; nearly 20% of prostatic malignant tumors originate in this
zone. And the central zone is made of approximately 25% of the prostate gland, and accounts for about 2.5% of
prostate cancers. The central zone has fewer incidences of malignant tumors, but its cancerous conditions
tend to be more aggressive.
All of those zones of
the prostate consist of different types of cell which has different function each. For instance, the epithelial
cells form the glandular portion of the prostate and they are the type of cells that recovers the prostatic wall
(the internal part of the prostate gland). Most prostatic cancers tend to develop from the epithelial cells. The
stromal cells, in the other hand, form the surrounding muscle and connective tissues. It is believed that complex stromal-epithelial
cellular interactions can lead to BPH (enlarged prostate). It
also believed that miscommunication betweenepithelial cells and stromal cells is often the cause
of many prostatic diseases.
Although all the prostate's
functions are not clearly known, the prostate gland plays various roles; its primary function, however, is
to produce and store the seminal fluid, a slightly alkaline and thick white liquid containing spermatozoa that is ejaculated by the male genital tract.
the prostate gland contacts its smooth muscles to propel the seminal fluid into the urethra. The prostatic fluid is expelled in the first ejaculate
fractions, together with most of the spermatozoa. Being alkaline, the semen helps neutralize the acidity of
the vaginal tract, thus prolong the lifespan of sperm.
To work properly, the prostate gland also
needs secretion of the male hormone called androgens. Also called androgenic
hormone or testoid, the androgens from a group of hormones that help to
stimulate and control the development and maintenance of male sex characteristics. Among of the androgens, there is
testosterone. Produced by the testes, the testosterone participates in the
formation and development of the testis and prostate. In addition, it also believed that the testosterone play a
major role in the formation of secondary sexual characteristics: increased muscle, bone mass and the growth of
In spite of its important functions, the
prostate is subject to many medical conditions, mainly: prostate cancer, prostatitis (Prostate infection), enlarged prostate (BPH). See each condition separately for more