A solid organ, the largest accessory gland of the male reproductive, approximately 3cm in length, 3.5 by 2.5cm, 20-25gm in weight, with its base upward and apex downwards surrounding the prostatic urethra. Normally, the prostate is quite small—it is nearly the same size and shape as a chestnut. It is located in front of the rectum, just below the bladder, and wraps around the urethra, the tube that carries urine from the bladder out through the tip of the penis.

Traditionally described in lobes it is now aptly divided into glandular areas (20%) –peripheral, central, transition and preprostatic zones; non-glandular (80%) - anterior fibromuscular area.

Each zone tends to have a disease entity peculiar to them.

The peripheral zone is similar to the transition zone. It constitutes 70% of the normal gland and is the part sampled during non ultrasound scan guided biopsy and is the site of origin of 70% of prostatic cancer.

Transition zone constitutes 5% of the normal gland. It is the site of BPH and 20% of prostatic cancer.

Central zone-makes up 20% of normal gland and 10% of cancer.

The prostate comprises of epithelium, basal, neuroendocrine, connective tissue and smooth muscle. Only epithelial cell secrete PSA therefore its increase only occurs when the disease entity especially cancer involves the epithelial cell.

Prostate capsule

- false: formed by compression of normal tissue in the peripheral zone by BPH

- true: formed from tissue around the gland. During prostatectomy, the false capsule is left intact, thus prostate cancer may occur even after a prostatectomy.

Function

Its exact function remains lucid. The prostate produces some of the fluid for semen, which transports sperm during the male orgasm.