Structure/Morphology
The mucosa of the tongue is separated into the mucosa coating the ventral aspect and the mucosa coating the dorsal aspect. The ventral mucosa is smooth and is adjoined to the floor of the oral cavity via the lingual frenulum. The dorsal mucosa of the tongue is involved in mastication and taste. It’s divided bilaterally by the longitudinal median sulcus.
The anterior two thirds of the dorsal mucosa faces superiorly, while the posterior one third lies posteriorly and faces the oropharynx and is continuous with pharyngeal mucosa. The epithelium on the dorsal aspect of the tongue is nonkeratinized posteriorly. However, anteriorly it is keratinized which may be due to its proximity to the external environment.
There are numerous raised elevations on the dorsal mucosa called papillae. These serve to increase the surface area and contain the taste buds. There are four main types of papillae: filiform, fungiform, foliate, and vallate papillae, the later three of which contain taste buds. These taste buds are most prevalent on the posterior region of the tongue but are also present in the pharynx.
Related parts of the anatomy
Key Features/Anatomical Relations
Posteriorly, the mucosa of the tongue is connected to the epiglottis via the glossoepiglottic folds (two lateral and one median folds). The depressions that sit between these folds are called the valleculae.
Additionally, the mucosa of the posterior one third of the tongue covers the lingual tonsil.
Function
The mucosa of the tongue acts as a barrier against the external environment, such as preventing injury, water loss, and microbial invasion. Additionally, the papillae of the dorsal mucosa of the tongue increase the surface area of contact and friction between food and of tongue and contain the taste buds.
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