Prostate
Prostata
ReproductiveGlandsPelvis
Shown on the male body.
- What it is
- Walnut-sized fibromuscular gland just below the bladder neck that encircles the first part of the urethra; it has transition, central and peripheral zones and is pierced by the two ejaculatory ducts.
- Function
- Adds a thin, slightly acidic fluid rich in PSA and zinc that makes up about 20–30% of semen and helps liquefy it.
- Size
- About 4 × 3 × 2.5 cm, 20–25 g in a young adult.
- Clinical note
- Benign enlargement of the transition zone squeezes the urethra in older men; most cancers arise in the peripheral zone, which can be felt through the rectum.