The vas deferens (HA8) is the duct that carries sperm from the epididymis toward the ejaculatory duct. Sperm (arrow) are stored in the vas deferens until emission. There are three distinct layers in its wall: an inner mucosa (m), a middle muscularis (SM), and an outer fibrosa (F). The muscularis contracts during emission to force the sperm out of the tract.