Angioarchitectural form, functional distributive pattern and classification of the filiform papillae on the crossbred Japanese cat tongue anterodorsal surface in scanning electron microscopic specimens

The purpose of this study was to undertake a three-dimensional comparative observation of the angioarchitectural form, functional distributive pattern and classification of the filiform papillae (FiP) as they appear on the entire dorsal surface of the front of the Japanese cat tongue using microvascular cast specimens (MVCS). By means of the corrosive resin casting technique, the MVSC of the FiP of the cat tongue were prepared and examined in detail under the scanning electron microscope (SEM). On the frontal half of the anterodorsal surface of the anterior tongue, types I-V of the FiP are arranged in the form of a A with the point in the direction of the apex and in an oblique line running from the antero-central to both postero-peripheral regions. In the rear half of the anterodorsal surface of the anterior part of the tongue, types I-V of the FiP are arranged in the form of a V with the point in the direction of the root and in an oblique line running from both antero-peripheral regions to the postero-median region or towards the pharynx on the anterior centro-dorsal surface of the tongue. The FiP, arranged in an oblique line running fron the central to the apical part of both the periphery and the pharyngeal region of the cat tongue, can be classified into five types (Types I-V) according to the shape and size of the main process (MP), numbers of the accessory processes (AP) and regional position of the lozenge arrangement. FiP Types I-III consisted of an MP which contained a large spoon-shaped and concave network process, and the AP contained a bundle of spin-like processes arranged radially at the anterior basal margin of the MP. FiP Types IV and V consisted only of MP. It was conjectured that the lozenge arrangement of the A and V form FiPs, classified into five types (Types I-V) from the frontal portion of the anterodorsal surface toward the pharynx on the front of the tongue, play a functionally assistant role in the mastication of food and sucking of liquid, including milk.