The Structural Organization and Functions of the Epithelium of the Vas Deferens

Abstract

The vas deferens is the least understood and studied organ of the male reproductive system. It is often considered as simply a tube whereby sperm exit the epididymis at the time of ejaculation, and even though vasectomy is the most common method of contraception in males, little is known about the structure and functions of the epithelial cells lining the normal vas, what regulates them, and their role in relation to sperm. It is well documented that humans do not have a bulbous cauda epididymidis as in the rat, and that sperm storage resides in what would be called the proximal vas deferens (Turner, 1991); data from vasectomized patients suggest that half the sperm in the human ejaculate can potentially derive from the distal vas and ampulla (Bedford, 1994). Thus the vas deferens, including that of humans, must play a role in the viability and protection of sperm from reactive oxygen species, proteases and complement during their storage (Hinton et al., 1996). There is even evidence for an active role of the ampulla of the vas in sperm maturation and nourishment (Bergerson et al., 1994), and it has been documented in the monkey, that only after sperm had reached the cauda and vas deferens that they attained their full vigor and ability to swim rapidly (Van Der Horst et al., 1999).