The conjunctival epithelium in domestic ruminants. II. Electronmicroscopic investigations

The basal cells of all types of epithelia in the domestic ruminants have a smooth surface in their proximal part or are furnished with branched cytoplasmic projections. The cytoplasm of many basal cells contains a few or many micropinocytotic vesicles, which can be arranged in a moniliform manner. The intermediate cells as well as the cells of the stratum superficiale - with the exception of the uppermost layers of the stratified squamous epithelium - are characterized by the presence of a great number of membrane-bound granules. Microvilli which project over the uppermost epithelial cells only occasionally contain a filamentous internal structure. The apical closure of the epithelium is preferentially formed by zonulae occludentes (tight junctions) with maximally 2-3 tight junction seals, they are followed proximally by 1-2 desmosomes. Zonulae adhaerentes can only rarely be observed. The nervous supply of the conjunctival epithelium which is best developed in the bulbusfacing side of the nictitating membrane is brought about by sub- and intraepithelial nerve-endings.