Morphologic variations along the length of the monkey vas deferens.

Gross and microscopic morphology of the vas deferens of sexually mature macaque monkeys were studied with special reference to the changes and modifications occurring throughout its entire length. The vas deferens was subdivided into four regional segments designated proximal, middle, distal, and ampulla. Each segment showed morphologic variations and it seemed to correspond roughly to the region located in a different part of the body which it traverses. The longitudinal folds of the epithelium are simple in the proximal region but gradually become more complex towards the distal region. In the ampulla, they often branch and form crypts. Stereocilia of epithelial cells are taller and more uniform in the proximal portion in comparison with the short, irregular stereocilia found in the more distal segment of the vas deferens. The luminal epithelial cells of the proximal part apparently have no granules or cytoplasmic blebbings, while the principal cells in the distal portion contain large numbers of cytoplasmic granules and apical blebs. Cells in the middle segments possess cytological features intermediate to the proximal and distal regions. These structural variations along the length of the vas deferens sug gest that this segment of the excurrent duct of the testis performs functions other than just as a passageway for spermatozoa.