Ultrastructure of the tongue and histochemical features of the lingual salivary glands in buzzards

Abstract

The macroscopic characteristics of the tongues of 8 long-legged buzzards are described and scanning electron microscopy was used to examine the epithelial tissue of the tongue's surface. Crossman's modified triple staining method and hematoxylin and eosin dye were used to determine the locations and general histological features of the lingual salivary glands. The nature of the glandular secretions was examined by staining with PAS, AB pH 1.0, AB pH 2.5, and PAS-AB pH 1.0 and pH 2.5, and diastase enzyme digestion. PAS staining and weak, moderate, and strong methylation procedures as well as sialidase and hyaluronidase applications were performed. We report the finding of focal accumulations of the anterior lingual salivary glands at the tongue's base with numerous duct openings in this area. This finding, in conjunction with the absence of taste papillae in the tongue epithelium, suggests that the role of the tongue in buzzards is to mix food with saliva and to move the food bolus rapidly to the back of the oral cavity. The acidic secretions of the lingual salivary glands not only have antimicrobial effects but also facilitate the swallowing process and may influence the digestive process in the distal parts of the alimentary tract.