Lingual Structure of the Domestic Pigeon (Columba Livia Domestica): A Light and Scanning Electron Microscopic Studies

Abstract

The aim of the present study was to investigate the light and electron microscopic structure of the tongue in pigeon. Six adult domestic pigeon (Columba livia domestica) of both sexes were used in this study. Results showed that the tongue is characterized by an elongated triangular format. Three parts are distinguished in the dorsal surface of the tongue: the apex, the body and the root of the tongue. On the dorsal surface of the apex and body of the tongue a median groove is found. Large conical papillae are located symmetrically in the form of the letter U in the marginal region between the body and root of the tongue.The mucosa of the tongue is covered with a thick stratified squamous epithelium which is cornified only on the ventral surface of the organ. The epithelium of the whole dorsal surface of the lingual apex and body presents the lamellar-shaped aspect. The dorsal surface of the root of the tongue, however presented smooth aspect with no densely packed desquamated cells. Microridges can also be seen clearly on the surface epithelium of the lingual root. Gustatory papillae are not found in the epithelium covering the tongue in the domestic pigeon. The PAS positive branched tubuloalveolar lingual salivary glands of the domestic pigeon composed of two laterally situated single strands, which extend from the apex of the tongue to the both sides of laryngeal cleft. The ventral surface of the tongue is devoid of any glandular structure. Neither the morphology nor the dimensions of the tongue show sex-specific differences. It was concluded that the unique features of the tongue in the domestic pigeon were the presence of the large conical papillae with a U-shaped arrangement between the body and the root of the organ and peculiar arrangement of lingual salivary glands.