Histological features of the tongue of the common pigeon (Columba livia)

Abstract

The study evaluated the histological characteristics of the tongue in ten adult common pigeons, with a view to highlighting the relationship between structure and function of the tongue in the common pigeon. The results showed that the entire dorsal surface of the tongue was covered by a non-keratinized stratified squamous epithelium, while the ventral surface of the tongue exhibited a keratinized stratified squamous epithelium in
the tongue body and apex. In addition, intraepithelial taste buds occurred in the dorsal epithelium of the tongue body and apex. The dense fibrous sub-epithelial connective tissue of the tongue root and body showed presence of mucus-secreting lingual glands and solitary lymphoid nodules. These were absent in the tongue apex. Furthermore, skeletal muscle fibres were abundant in the root and body of the tongue but not in the
tongue apex. A paraglossum composed of hyaline cartilage was situated in the core of the tongue, extending from the tongue body to the tongue apex. In longitudinal section, the papillary crest appeared as evaginations of the dorsal lingual epithelium at the boundary between the root and body of the tongue. The evagination, composed entirely of epithelial cells lacked a connective tissue core. It was concluded that these histological
features are essential adaptations that support the functions of the tongue during food intake, especially in the common pigeon which feeds mainly on grains and seeds.

Keywords: Common pigeon, Columba livia, Tongue, Lingual Epithelium, Lingual gland, Intraepithelial taste bud