5 - The oral mucosa

Abstract

This chapter discusses the function of the oral mucosa. The knowledge of the normal oral mucosal metabolism is important in understanding the many oral soft tissue lesions that occur in the mouth. The oral mucosa comprises a surface epithelium overlying a layer of connective tissue. This stratified squamous epithelium undergoes mitosis, synthetic activity, and disintegration, leaving the underlying cells as a cohesive tissue. The oral mucosal epithelium comprises of several cell layers: stratum germinativum, stratum spinosum, stratum granulosum, and stratum corneum. The epithelium of the oral mucosa is typically supported by a basement membrane zone, the papillary and reticular zones of the lamina propria, and beneath these the submucosa. The extracellular matrix of the basement membrane plays roles in epithelial attachment, cell differentiation, and permeability. In addition to the metabolic activities common to most cells, epithelial cells undertake a number of specialized synthetic activities associated with the maintenance of a surface barrier. It helps in the synthesis of keratin, the degradation of other intracellular organelles, the synthesis of cell surface and extracellular components related to cell adhesion and barrier function, and the synthesis of the basement membrane complex that provides attachment of the epithelium to the underlying connective tissue.