FUNCTIONAL AND COMPARATIVE STUDY OF THE CIRCUMVALLATE PAPILLAE IN FOUR SPECIES OF MAMMALS

Document Type : Original Article

Authors

1 Lecturer of Oral Biology, Faculty of Dentistry, Tanta University, Egypt

2 Ass. Professor of Oral Biology, Faculty of Dentistry, Tanta University

Abstract

Introduction: The mammalian tongue displays significant morphological differences. These differences seemed to be related to the nature of food. Also, the surrounding environmental conditions play an important role in these differences. The dorsal mucosa of the tongue is covered by numerous papillae. In many mammals, tongue papillae play a vital role in food intake and digestion.
The aim study: This study was to investigate the morphological characteristics of the circumvallate papillae (CVPs) of rat, dog, rabbit and goat.
Materials and Methods: For this purpose, tongues of these animals were examined macroscopically as well as with light and scanning electron microscope (SEM).
Results: Grossly observations reveled, in ratsa single large CVP surrounded by a semicircular moat and an indistinct annular pad. In dogs, five CVPs were arranged in two lines. The large papillae were surrounded by a wide moat and a prominent annular pad.  Whereas, the small papilla lacked the annular pad and had irregular ridges.In rabbits, two CVPs enclosed by a deep moat lacking the annular pad. Whereas, goats had eight pairs of CVPs on both rims of the torus linguae and were encircled by a prominent gustatory moat and a thick annular pad. Histological examination of the four species revealed taste buds were located in the medial and lateral walls of the moat except for goats that had taste buds only in the medial wall of the moat. SEM examinationof the papillary surface exposedtransverse grooves in rats, irregular microridges and grooves in dogs and rabbits whereas the goats showed very little and small grooves.
Conclusion: Hence, this study highlighted a variation in the morphology and microscopic anatomy of CVPsas an adaptation to their different feeding behaviours.
 

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