Image: Princess Margaret Cancer Centre, Canada
The prostate gland is about the size of a walnut, and surrounds the neck of the bladder and urethra—the tube that carries urine from the bladder. It is partly muscular and partly glandular with ducts opening into the prostatic portion of the urethra. It is made up of 3 lobes: a center lobe with 1 lobe on each side. The prostate gland secretes a slightly alkaline fluid that forms part of the seminal fluid, a fluid that carries sperm.