Prostate

Information about PROSTATE HEALTH can be found here.

 

Where is the prostate gland located?

The prostate gland is located in the pelvis just above the pelvic floor where it is surrounded by the levator ani muscles. It is located between the bladder and the penis. The prostate is shaped like doughnut, with the urethra passing through the middle of the prostate. In fact, the part of the urethra which traverses the prostate is called the 'prostatic urethra' which can be seen during cystoscopy. The parenchyma (substance) of the prostate cannot be seen with a cystoscope, much like the inside of doughnut cannot be seen by looking through the hole. The bladder neck fuses with the prostate to provide a funnel-shaped outlet for the bladder.

 

The reproductive tract merges with the urinary tract at the level of the prostate. The seminal vesical glands and vas deferens insert into the base of the prostate. Secretions from these glands mix within the lumen of the prostate before ejaculation occurs.

 

 

What does the prostate do?

The prostate serves a number of functions.

  1. Continence: the prostate is part of the 'internal urinary sphincter'.
  2. Reproduction: the prostate contributes fluid to the ejaculate and the lumen of the prostate is the area where sperm is mixed with the other secretions which form semen.
  3. Immunologic: the prostate may play a role in preventing bladder infections.

When the prostate becomes diseassed, it can affect all of these functions. In addition, surgery on the prostate may affect these functions as well.

 

What is the anatomy of the prostate gland?

The prostate gland consists of (1) a glandular component and (2) a stromal component. These 2 components are found throughout the gland which is structurally composed of different lobes and zones.

 

The glandular component is responsible for producing and secreting fluid which eventually ends up in the ejaculate. The glandular component is organized much like a tree with a major trunk draining each lobe which is served by many smaller ducts which progressively branch out into smaller and smaller ducts. At the end of the ducts are acini, much like leaves are found at the end of tree branches. There are approximately half a million acini in the prostate. The acinus is the smallest structural component of the gland. In the prostate, they are shaped like cul de sacs but instead of houses lining a cul de sac, the acini are lined by secretory epithelial cells. Each cell secretes a small amount of fluid which, when combined with that of all of the other prostate epithelial cells, produces about 20% of the ejaculatory volume. The acini are surrounded by something called a baesment membrane which is meant to separate the epithelial cells from the surrounding structures. Benign proliferation of acini results in BPH whereas proliferation of cells through the basement membrane results in cancer.