Ductus deferens

The ductus deferens primary function is to transport sperm cells from the epididymis to the ampulla close to the seminal vesicles and out to the urethra. The ductus deferens also store sperm before ejaculation. The tubes begin at the end of epididymis posterior to the scrotum and ascend to the urinary bladder where it passes and descend towards the prostate and seminal vesicles. The end of the ducts is called the ampulla, which is a region where the tubes get wider in diameter. The walls within the ductus deferens consist of smooth muscle with ciliated pseudostratified columnar epithelium and elastin fibers bundles. These muscles contract with peristaltic movements when ejaculation is anticipated, in this way forcing the sperm cells forward. Before the sperm enters the urethra it collects fluids from the prostate and the seminal vesicle to complete the ejaculate. The sperm can be stored in the ducts awaiting ejaculation and old, unused sperm cells will be broken down and absorbed in the ducts.