A stratified epithelium is one with more than one cell thickness on the basement membrane. In this case the epithelium is many layer thick. Its cells are also flat and polyhedral suggesting they are squamous cells. Hence the epithelium is stratified squamous epithelium.

The basement membrane is clearly visible as darkly staining in the basal part of the epithelium. It marks the end of the epithelium and the beginning of the lamina propria,  a connective tissue structure which is highly vascularized with many nerve endings that is part of the mucosa. The mucosa itself has three structures in the gastro- intestinal system and two in other areas- epithelium, lamina propria and muscularis mucosae. Muscularis mucosae is absent in tissues other than the gastrointestinal system