To better understand prostate cancer, it helps to understand the anatomy of the prostate gland.

The prostate gland is a male organ that is part of the lower genitourinary system. It lies between the base of the penis and anus.

The prostate is made up largely of muscle and gland tissues. This gland is about the size of a walnut. It usually weighs about one ounce. The urethra drains urine from the bladder, through the prostate, and exits at the penis.

The prostate makes fluid that becomes part of the semen. The semen also contains sperm from the testicles.

Anatomy examples:

• Cross section of the prostate gland
• Bladder and lower urinary tract in men
• Side view of bladder and prostate
• Genitourinary system