Morphophysiology of the epididymis of the African sideneck turtle (Pelusios castaneus): Histological, microstereological and ultrastructural approach

This study was carried out to describe the morphophysiology of the epididymis of the adult African sideneck turtle using histological,  microstereological and ultrastructural methods. The epididymal duct lies within a relatively thin sheath of connective tissue, and is lined by pseudostratified columnar epithelium. Unlike luminal diameter and stereocilial height, epithelial height, as well as the population of principal cells, decreased from the proximal to posterior segment. The clear cells of the turtle epididymis are limited to the posterior segment of the duct. Basal and apical cells as well as intraepithelial lymphocytes are all distributed across the three segments of the epididymis while macrophage-like cells are absent throughout the length of the duct epithelium. The structure of the African sideneck turtle epididymis demonstrates, as in most mammals and few reptiles studied to date, obvious regional differentiation of the duct epithelium with evidences of secretory and endocytotic abilities as demonstrated by the contents of highly developed endoplasmic reticulum and secretory blebs in the principal and basal cells as well as clear cells, believed to be concerned with endocytosis. The outcome of the study is expected to be useful in the comparative structural and functional anatomyof turtle epididymis. Keywords: African sideneck turtle; epididymis; ultrastructure; microstereology; principal cell