Morphology of Lingual Papillae of Bear: Light Microscopic and SEM Study

The morphology and histology of the tongue in two adult Asian bears were examined by light and scanning electron microscopy. Four types of papillae; filiform, conical, fungiform and vallate were observed on the dorsaum lingua. Numerous filiform papillae were visible on the lingual apex and body, while, fungiform papillae were scattered among them. The discoid-shaped fungiform papillae were more densely on the lingual apex. The filiform papillae were extended to the lateral margin of the lingual body. They were transformed into the conical papillae on the caudal part of the lingual body and root. Totally, 14-16 of spheroid and oval vallate papillae at different sizes were present on the root of the tongue. The foliate papillae were absent. Histological sections showed that the conical papillae represented a flat pyramidal shape with several slender accessory processes. The tongue was covered by a keratinized stratified squamous epithelium. A dense connective tissue composed the lamina propria and thick masses of striated muscles constituted the bulk of the tongue. The lamina propria didn't penetrate completely into the filiform papillae of the lateral margin. Numerous forms of lingual salivary glands with seromucous secrations were intermingled with the lingual muscles in the lingual root.