Histochemical and ultrastructural research of the epithelium of the head of the epididymis of Equus asinus
Romanello, M.G.; Arrighi, S.; Domeneghini, C.; Rizzotti, M.
Schweizer Archiv für Tierheilkunde 127(10): 671-684
1985
ISSN/ISBN: 0036-7281 PMID: 4071022 Document Number: 244180
The epithelium of the head of the epididymis in Equus asinus consists of main cells, basal cells, apical cells and cells with residues. However, elements which correspond to clear or light cells are missing, and the same applies to "narrow cells" and so-called holocrinic cells. None of the regional differences, such as occur in other species, could be found. The numerically predominant main cells are cylindrical in form. In the apical cytoplasm the presence of microvilli, "caveolae", vesicles, multivesicular bodies and lysosomes is a sign of intensive absorptive activity, while the remarkable development of the endoplasmic reticulum and the Golgi apparatus indicates a simultaneous synthetic activity. The possible mechanisms of secretion are discussed. In the basal section there are granules similar to those in the enterochromaffin cells. The basal cells lie deep in the epithelium and are not connected with the lumen. They do not seem to participate in the epithelial turnover. The apical cells are less numerous and are situated between the main cells. They are long and thin and widen out in the direction of the lumen. They are apparently capable of affecting the epididymal fluid by means of an active exchange of ions with the lumen. The cells with residues are localized in the basal third of the epithelium and are filled with a compact material which shows the characteristics, both histochemical and ultrastructural, of lipofuscin. Their possible origin is discussed.