The testes are where sperm is manufactured. The epididymis is a long coiled structure topping the testis, and it receives immature sperm from the testis and stores it several days. When ejaculation occurs, sperm is forcefully expelled from the tail of the epididymis into the vas deferens. Sperm then travels through the vas deferens through up the spermatic cord into the pelvic cavity, over the ureter to the prostate behind the bladder. Here, the vas deferens joins with the seminal vesicle to form the ejaculatory duct, which passes through the prostate and empties into the urethra. When ejaculation occurs, rhythmic muscle movements propel the sperm forward.