The prostate gland is part of the male reproductive system. The prostate is located below the bladder. It surrounds the urethra, the tube that carries urine and semen out of the body. The function of the prostate is to produce fluid. This fluid mixes with fluid from the seminal vesicles and sperm from the testicles to form semen. During ejaculation, semen travels through the urethra and out of the penis. Prostate health is closely linked to hormones, chemicals that carry messages throughout the body. Normal levels of hormones, such as testosterone, keep the prostate working correctly.