Male reproductive system. Computer illustration showing a section through the male reproductive organs and genitals, with the penis in an erect state. At lower centre is one of the testes, with the spermatic ducts (vas deferens) running from the epididymis on the testis to the prostate gland (small, centre-right). These structures supply sperm, seminal fluid and other secretions to form the ejaculate during sexual intercourse. Also shown are the bladder (round, centre), and rectum (right).