The fine structure of the ductuli efferentes of the opossum.

Abstract

AbstractThe fine structure of the straight portions of the ductuli efferentes of the opossum were studied by light and electron microscopy. Two cell types, a ciliated and non‐ciliated cell, characterize the simple columnar epithelium that lines the ductuli. The non‐ciliated cell possesses an extraneous coating of the luminal plasma‐lemma, aggregations of apical canaliculi, and vacuoles of varying density distributed in the supranuclear cytoplasm. Such morphological criteria have been regarded as suggestive evidence for absorptive function. The epithelium rests upon a thick basement membrane beneath which are variable amounts of smooth muscle and connective tissue elements.Observations of the structure of the simple squamous epithelium lining the processus vaginalis are reported.Myelinated and unmyelinated nerves are found in the adnexa of the ductuli. These are enclosed in a thin, cellular investment, the innermost layer of which is usually incomplete. This cellular wrapper is considered a “perineural epithelium” but its characteristics are at variance with those found in the recent literature.