Ductus Deferens The ductus deferens(duk tus defer-enz, defero, to carry away), or vas deferens, emerges from the epididymis and as cends along the posterior side of the testis to become associated with the blood vessels and nerves that supply the testis. These structures form the spermatic cord(see figure 19.5a). Each spermatic cord consists of the ductus deferens, testicular artery and veins, lymphatic vessels, and testicular nerve. It is sur- rounded by the cremaster muscle, and two connective tissue sheaths. Each ductus deferens extends, in the spermatic cord, through the abdominal wall by way of the inguinal canal. Each ductus deferens then crosses the lateral wall of the pelvic cav- ity and loops behind the posterior surface of the urinary blad- der to approach the prostate gland(see figures 19.2 and 19.5a). The total length of the ductus deferens is about 45 cm. Just before reaching the prostate gland, the ductus deferens in- creases in diameter to become the ampulla of the ductus deferens(see figure 19.5a). The wall of the ductus deferens contains smooth muscle. Peristaltic contractions of the smooth muscle propel the sperm cells from the epididymis through the ductus deferens.