Scanning electron microscopic observations of the vas deferens in man and monkey with special reference to spermiophagy in its ampullary region.

The vasa deferentia of men and monkeys were studied and compared with special attention to spermiophagy by epithelial cells in the ampullary region. Specimens were obtained from adult men who were subjected to total vasectomy for early prostatic cancer and from healthy adult Japanese monkeys (Macacus fuscatus). The vasa do not differ greatly in gross and microscopic morphology between man and monkey. The mucosal lining of the vas, except for its ampullary region, is generally smooth with occasional infoldings and consists of a pseudostratified columnar epithelium. The free epithelial surface is covered by dense mat of long microvilli (stereocilia) on which a few spermatozoa reside. In contrast to other regions of the vas, the ampullary lumen has a spindle-shaped dilation and complicated infoldings of the mucosa, the mucosa is wider and much more infolded in man than in monkey. The columnar epithelial cells characteristically contain abundant secretory granules in the cytoplasm and bear short, stubby microvilli in the place of stereocilia. Worthy of special mention in the ampullary region of the vas in both species is that various stages of spermiophagy by the epithelial cells are extensively visualized by SEM. The ampullary region may play a role in the removal of excess spermatozoa in addition to the storage of them.