COMPARATIVE HISTOLOGICAL STUDY OF TONGUE IN TWO SPECIES OF RAT (RATTUS NORVEGICUS & RATTUS WISTAR)

This study was carried out to compare the anatomical structure of tongue in two species of Rattus. For this purpose, the tongue of Rattus norvegicus (8 adult male) and Rattus wistar (8 adult male) was dissected from the root. Macroscopic features of tongue as weight, length and width were measured by calliper. Then, they were fixed in formalin (10%) and prepared by tissue processing. The sections (5 μ) were prepared and subjected to Haematoxylin and Eosin stain. Morphometric analyses were performed by light microscopy and progress capture soft ware. The comparative observation in these species were showed that the keratinized stratified squamous epithelium covered dorsal of tongue especially on apex and the lingual torus was on the posterior third. The layers and arrangement of them were similar together but and different in thickness. Nnumerous filiform papillae as mechanical papillae and a few fungiform and one circumvallate papillae as gustatory papillae were observed on dorsum of tongue. Distribution and density of filliform and fungiform papillae were different. Lingual glands were found spatially on posterior of ventral surface. According to these results, the structure of tongue in both species is somewhat similar and differences due to adaptations for verity of diet.