Lining epithelium , i.e. non-keratinised stratified squamous epithelium, covers the remaining surfaces of the oral cavity. The dorsal surface of the oral part has a characteristic appearance due to the presence of a large number of small projections, the lingual papillae. The epithelium of the pharyngeal part forms a somewhat irregular surface which covers the lingual tonsils. The lingual papillae consist of a connective tissue core covered with a stratified squamous epithelium. On the basis of their appearance four types of papillae can be distinguished - filiform, fungiform, circumvallate and foliate papillae .
Filiform papillae are the smallest and most numerous papillae.
By providing the tongue with a rough surface they aid in the manipulation and processing of foods. Prof. Oxnard brought another function to my attention, i.e. the cleaning of the surfaces of the mouth, in particular the teeth. Fungiform papillae occur singly and are fairly evenly spaced between the filiform papillae. Their connective tissue core is richly vascularised. The epithelium is slightly thinner than on the remaining surface of the tongue.