Male urogenital system, artwork. At top is the bladder which passes urine out through the urethra (tube) in the centre of the penis (lower centre). Either side of the penis are the testes (testicles), which produce sperm. Sperm is carried from the testes in the vas deferens (tube, upper left) through the ejaculatory ducts (not seen) and prostate gland (centre, below the bladder), and into the urethra, before passing out through the penis. Below the prostate gland are the cowper's glands.