The vas deferens is a muscular tube in the male reproductive system that transports sperm from the epididymis to the ejaculatory duct. It is part of the pathway that sperm take during ejaculation, playing a crucial role in male fertility. This tube is approximately 30 centimeters long and is surrounded by smooth muscle that contracts to propel sperm forward. The vas deferens connects to the seminal vesicles, where seminal fluid is added to create semen, which is then expelled during ejaculation.