What is it?

The prostate gland is part of the urinary and reproductive systems of the male (Figure 1). Women do not have a prostate gland. The prostate is just below the bladder. Its size can be anywhere from that of a walnut to a small apple, and its 2 semicircular lobes (left and right) encircle the urethra, which is the tube that carries urine from the bladder and down through the penis.

Frontal view

Figure 1

Frontal view

The prostate gland is normally rubbery, pliable, and smooth. Because it is next to the rectum, the physician is able to feel its size and consistency with a gloved finger during a rectal exam. If it feels enlarged or hard or there is a hard lump, then this is an indication that the prostate has undergone a change, not necessarily cancer. If it is swollen, sore and soft it may be infected.

What does the prostate gland do?

The prostate gland has 2 functions. Because it surrounds the urethra, its muscle fibres squeeze the urethra slightly and helps control the flow of urine. Its second function is the production of fluids that are added to the seminal fluid (semen).

The prostate gland is made up of thousands of tiny fluid-producing glands interspersed within its blood vessels and muscular framework (Figure 2). It is estimated that 80% of the fluid released during ejaculation comes from the prostate gland. Sperm travels from the testicles upwards through the tube called the vas deferens and back down through the prostate gland where they mix with prostate fluid. The prostate drains its ejaculatory fluid from its tiny glands into larger tubes or ducts which then drain into the urethra. Immediately above the prostate gland are the seminal vesicles, which store sperm and ejaculatory fluid. These vesicles are considered to be an extension of the prostate gland.

The prostate contains many glands and ducts

Figure 2

The prostate contains many glands and ducts

During ejaculation, the muscular sphincter at the base of the bladder tightens and closes, preventing urine from passing down the urethra. The ejaculate, now containing both sperm and fluid, flows from the ejaculatory ducts into the urethra, where it passes out through the end of the penis.

Excerpt from the Intelligent Patient Guide to Prostate Cancer by S. Larry Goldenberg, MD 
in association with the MediResource Clinical Team