Fine Structure of Mucus Granules in Rumen Epithelium

Rumen epithelium is a parakeratotic, stratified squamous epithelium which functions in metabolism, absorption, and protection. In previous light microscope histochemical studies (1, 3) and electron microscope studies (2) on this tissue, phenomena characteristic for both mucus-producing and keratinizing epithelia were described. The presence of mucus was demonstrated histochemically (1, 3) by the periodic acid-Schiff (PAS) reaction which exhibited a gradation in intensity ranging from weakly stained spinous cells to intensely stained horny cells. Electron microscope studies (2) described the differentiation products seen in both keratinizing and mucusproducing epithelia. Filaments are found in