Microscopical study regarding the arrangement of tongue muscle in Chinchillas (Chinchilla lanigera)

Abstract

The tongue in mammals is essential for food consumption, oral transport, swallowing, emesis, respiration, coughing. Depending on species, the morphological features of the tongue vary according to the lifestyle and type of diet. The aim of the study was to present the main microscopical features of the tongue in Chinchilla. The biological material was represented by 5 Chinchillas. Longitudinal fragments were collected from the tongue, fixed in the Stieve solution, histologically processed by paraffin technique and stained later by Goldner’s trichrome method. In Chinchilla’s tongue, the myofibers are oriented longitudinally, transversally, vertically and occasionally in an oblique way. The myofiber bundles are arranged in a superficial dorsal layer, a ventral layer, while the central axis of the organ occupies the space between the two superficial layers. The superficial dorsal layer extends from the tip of the tongue to the intermolecular protuberance. It is thin and plexiform on most of the free portion of the organ but gradually thickens towards the body of the tongue where the cells are predominantly longitudinally and partially oblique. The ventral superficial layer is relatively thin in the free portion of the tongue, consisting mainly longitudinal and scattered vertical or horizontal cells. In the body region of the tongue, the ventral superficial layer is thicker and arranged in two oblique layers (i.e., ventral and dorsal). The central axis of the tongue includes myofibers with a vertical and horizontal orientation. The specific layout of myofiber bundles in Chinchilla’s tongue could be related to the specific way of food prehension, mastication and oral transport of feed in this species.