The prostate is a walnut-sized gland belonging to the male reproductive system situated below the urinary bladder and in front of the rectum, surrounded by the urethra, which is a tube-like structure running from the bladder to the penis.
Above the prostate gland, there are seminal vesicles that are a pair of tube-shaped glands, which secrete significant portion of the fluid in the semen. The seminal vesicles join with the ductus deferens, which carries sperms from the testicles and together they form the ejaculatory duct which passes through the prostate gland and joins the urethra.
Source: Modasta