The mucosa lining the oral cavity varies significantly in its structure and function. In some
areas of the mouth, it protects the underlying structures; in others, it provides a means of transepithelial
absorption and around the teeth it provides a unique epithelial structure and controls passage of
crevicular fluid. This chapter reviews briefly the major structural characteristics of the cells of oral
epithelium and connective tissue. The elementary cell mechanisms and functions of keratinocytes and
every cell of the connective tissue are also briefly analyzed.