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Cross section of the mid-region of the tongue of a young pigeon (HE)
In cross section, the tongue of a bird has a rather triangular shape, conforming the shape of the lower beak. The entoglossal bone (os entoglossum) is lying centrally in the body of the tongue, initially consisting of two paired cartilage parts that will fuse and ossify partially or completely when the bird matures. At the micrograph above, the entoglossal bone is still cartilaginous.
The musculature of a birds' tongue is poorly developed: only ventrally a layer of longitudinal striated muscle is found.
In the mid-region of the tongue, lingual salivary glands (gll. linguales rostrales et caudales) are imbedded in the connective tissue dorsally and dorso-laterally of the entoglossal bone. Posteriorly in the tongue, the glands will form a layer underlying the dorsal epithelium. In the anterior tip of the tong, no glands are found.
Birds possess little taste buds. Taste buds occur in the epithelium of the pharynx and the epithelium of the caudal part of the base of the tongue. Only at the caudal part of the dorsum of the tongue, one or more transverse rows of mechanical papillae (papillae linguales) are found.