The male prostate gland acts as an exocrine gland in the male reproductive system. It is a firm, partly muscular, chestnut sized gland near the neck of the urethra in males.

Formation and Orientation

The prostate is usually formed within the ninth week of the embryonic stage in reproductive development.

The prostate can be separated into either “lobes” or “zones”. When looking at a prostate divided into zones, there are four distinct regions. The first zone is the Peripheral Zone which is the part of the prostate gland that surrounds the distal urethra. The next zone is the Central Zone which encompasses the ejaculatory ducts. The Transition Zone is the area around the proximal urethra, growing throughout life. The final zone is the Anterior Fibromuscular Zone which is self-explanatory, being composed of fibrous tissues and muscle.

When looking at the prostate gland in terms of lobes, you can see that each of the four lobes corresponds to one or more zone. The isthmus (anterior lobe) parallels part of the Transitional Zone, the posterior lobe corresponds to the Peripheral Zone, the lateral lobes span all zones and the median lobe is linked to part of the Central Zone.

When the prostate is stimulated, ejaculation occurs which sends sperm through the ductus deferens, then into the male urethra through ejaculatory ducts. Prostatic secretions are composed of proteolytic enzymes, prostatic acid phosphatase, β-microseminoprotein, prostate-specific antigen and a small amount of zinc. The prostate is mainly regulated by the male hormone dihydrotestosterone.


The prostate works to secrete the majority of the alkaline fluid that makes up semen. Because of the alkalinity that the prostate gland provides to the semen, the sperms’ lifespan is elongated when put against the acidity of the vaginal tract. The prostate is also slightly composed of smooth muscle that helps to eject seminal fluids during ejaculation.

Image Caption: Prostate and bladder, sagittal section. Credit: National Cancer Institute / Wikipedia