The tongue is made up of several muscles, is richly supplied with blood vessels and nerves, and is covered by highly specialised MUCOUS MEMBRANE. It consists of a free part known as the tip, a body, and a hinder ?xed part or root. The under-surface lies upon the ?oor of the mouth, whilst the upper surface is curved from side to side, and still more from before backwards so as to adapt it to the roof of the mouth. At its root, the tongue is in contact with, and ?rmly united to, the upper edge of the LARYNX; so that in some persons who can depress the tongue readily the tip of the EPIGLOTTIS may be seen projecting upwards at its hinder part.
Structure The substance of the tongue consists almost entirely of muscles running in various directions. The tongue also has numerous outside attachments: one muscle on each side unites it to the lower jaw-bone just behind the chin, and this muscle serves to protrude the tongue from the mouth; other muscles, which retract the tongue, attach it to the hyoid bone, the larynx, the PALATE, and the styloid process on the base of the SKULL.
The mucous membrane on the undersurface of the tongue is very thin. In the middle line, a fold of mucous membrane, the frenum, passes from the under-surface to the ?oor of the mouth; when this frenum is attached too far forwards towards the tip of the tongue, the movements of the organ are impeded – the condition being known as tongue-tie. On the upper surface or dorsum of the tongue, the mucous membrane is thicker, and in its front two-thirds is studded with projections or papillae, most of which are conical. Some of them end in long ?laments, and are then known as ?liform papillae. On the tip, and towards the edges of the tongue, small, red, rounded fungiform papillae are seen, which act as end-organs for the sense of taste – as do circumvallate papillae, each of which is surrounded by a trench along which open numerous taste-buds. These taste-buds are also found in the fungiform papillae, scattered over
the throat, FAUCES, and palate. Five nerves, originating from the ?fth, seventh, ninth, tenth and 12th cervical nerves supply the tongue.... tongue
Health Encyclopedia