Tongue

Tongue. The tongue is mainly composed of muscular tissue, and is covered with mucous membrane, which presents a remarkable development of the structures known as papillae. These papillae are of three kinds - the circumvallate palillae are situated in two V-shaped lines at the base of the tongue, and consist of eight or ten rounded elevations, each of which has a central depression; the fungiform papillae are distributed mainly over the tip and sides of the tongue; the filiform papillae, simple conical elevations, are numerously distributed over the whole surface of the tongue. The tongue is possessed of ordinary sensibility, and contains the nerve terminations concerned with the special sensations of taste (q.v.); it plays, moreover, an important part in the modification of speech sounds and in the muscular actions of mastication and swallowing.

Diseases of the Tongue. The mucous membrane of the tongue is apt to be affected by inflammation or glossitis, and in this form of disease the deeper parts of the tongue are sometimes involved, leading, it may be, to abscess formation, or, in rare instances, to permanent hypertrophy of the organ. White patches are sometimes met with on the surface of the tongue, a condition known as leucoplakia. Ulceration of the tongue occurs in connection with digestive disturbance and with syphilis, or from the irritation caused by a sharp edge of an injured tooth. The tongue is an organ which is not uncommonly affected by the form of known as epithelioma.