Oral anatomy and tissue types.

The gross and microscopic anatomy of the oral cavity and its contents are discussed from the perspective of their function. Histologically, the oral mucosa is classified into three categories, lining, masticatory, and specialized. The epithelium of the lining mucosa is nonkeratinized stratified squamous, whereas that of the masticatory mucosa is ortho- or parakeratinized, to protect it from the shearing forces of mastication. Specialized mucosa possesses taste buds, small epithelially derived structures responsible for the perception of taste sensation. The subepithelial connective tissue of the lining and masticatory mucosae interdigitate with their epithelia, and the degree of interdigitations is directly correlated with the strength of the shearing forces acting on the mucosa. The oral mucosa also participates in the immunological defense of the oral cavity due to the presence of Langerhans cells, antigen presenting cells in the epithelium.