The Anatomy of Tongue

TONGUE

The tongue, together with its associated muscles, forms the floor of the oral cavity. It is and accessory structure of the digestive system composed of skeletal muscle covered with mucous membrane. The tongue is divided into symmetrical lateral halves by a median septum that extends throughout its entire length and is attached inferiorly to the hyoid bone. Each half of the tongue consists of an identical complement of extrinsic and intrinsic muscles.

The extrinsic muscles of the tongue originate outside the tongue and insert into it. They include the hyoglossus, genioglossus, and styloglossus. The extrinsic muscles move the tongue from side to side and in and out. These movements maneuver food for chewing, shape the food into a rounded mass, and force the food to the back of the mouth for swallowing. They also form the floor of the mouth and hold the tongue in position. The intrinsicmuscles originate and insert within the tongue and alter the shape and size of the tongue for speech and swallowing. The intrinsic muscles include the longitudinalis superior, longitudinalis inferior, transverses linguae, and verticalis linguae. The lingual frenulum, a fold of mucous membrane In the midline of the undersurface of the tongue, aids in limiting the movement of the tongue posteriorly.

The upper surface and sides of the tongue are covered with papillae, projections of the lamina propria covered with epithelium. Filiform papillae are conical projections distributed in parallel rows over the anterior two-thirds of the tongue. They are whitish and contain no taste bud. Fungiform papillae are mushroomlike elevations distributed among the filiform papillae and are more numerous near the tip of the tongue. They appear as red dots on the surface of the tingue, and most of them contain taste buds. Circumvallate papillae, 10 to 12 in number, are arranged in the form of an inverted V on the posterior surface of the tongue, and all of them contain taste buds. 

The Anatomy of Mouth (Oral Cavity)

MOUTH (ORAL CAVITY)

The mouth, also referred to as the oral or buccal cavity, is formed by the cheeks, hard and soft palates, and tongue. Forming the lateral walls of the oral cavity are the cheeks – muscular structures covered on the outside by skin and lined by nonkeratinized stratified squamos  epithelium. The anterior portions of the cheeks terminate in the superior and inferior lips.

The lips (labia) are fleshy folds surrounding the orifice of the mouth. They are covered on the outside by skin and on the inside by a mucous membrane. The transition zone where the two kinds of covering tissue meet is called the vermilion. This portion of the lips is nonkeratinized, and the color of the blood in the underlying blood vessels is visible through the transparent surface layer of the vermilion. The inner surface of each lip is attached to its corresponding gum by a midline fold of mucous membrane called the labial frenulum.

The orbicularis oris muscle and connective tissue lie between the external integumentary covering and the internal mucosal lining. During chewing, the cheeks and lips help keep food between the upper and lower teeth. They also assist in speech.

The vestibule of the oral cavity is bounded externally by the cheeks and lips and internally by the gums and teeth. The oral cavity proper extends from the vestibule to the fauces, the opening between the oral cavity and the pharynx or throat.

The hard palate, the anterior portion of the roof of the mouth, is formed by the maxillae and palatine bones, is covered by mucous membrane, and forms a bony partition between the oral and nasal cavities. The soft palate forms the posterior portion of the roof of the mouth. It is an arch-shaped muscular partition between the oropharynx and nasopharynx and is lined by mucous membrane.
Hanging from the free border of the soft palate is a conical muscular process called the uvula. On either side of the base of the uvula are two muscular folds that run down the lateral side of the soft palate. Anteriorly, the palatoglossal arch (anterior pillar) extends inferiorly, laterally, and anteriorly to the side of the base of the tongue. Posteriorly, the palatopharyngeal arch (posterior pillar) projects inferiorly,nlaterally, and posteriorly to the side of pharynx. The palatine tonsils are situated between the arches, and the lingual tonsil are situated between the arches, and the lingual tonsil is situated at the base of the tongue. At the posterior boder of the soft palate, the mouth opens into the oropharynx through the fauces.