An electron microscopic investigation of rumen mucosa

Bovine rumen mucosa, capable of functioning in absorption, metabolism, and protection, appeared in the electron microscope as a parakeratotic stratified squamous epithelium. Cells comprising the substratum basale contained abundant metabolic organelles and numerous large vesicles, which were postulated to function in the assimilation and metabolism of products absorbed from the rumen. Cells that comprise the substratum spinosum contained aggregates of filaments and membrane-bounded mucous granules revealing differentiation directed toward mucus formation. The presence of both keratohyaline and mucous in granular cells is indicative of differentiation directed toward keratinization and mucus production. Partially keratinized, mucus-containing horny cells with fuzzy-coated microvillus extensions comprised the stratum corneum. These specific horny cells afford protection and permit absorption to occur.