[Morphology and microvascular architecture of the filiform papillae in the rat].

This study was an attempt in order to investigate microvascular architecture in various kinds of the filiform papillae of the rat utilizing the plastic injection method. Filiform papillae of the rat were grouped into three types; the simple and the giant conical and the true filiform. Additionally, the simple conical papillae could be subgrouped into type I, II and digitiform papillae, and the forked filiform as an intermediate form between the giant conical and the true filiform, based on their function and microvasculature. The capillary loop of the true filiform papillae was the simplest, hair-pin loop. The basic form of the loop was similar to the loop of the simple conical type I, II, and digitiform papillae respectively, although that of type II, having two or three ascending crura, was the most complicated of the three. Capillary loops of the giant conical papillae consisted of three or five ascending crura which passed upward in the pharyngeal side, the descending crura consisted or similar capillaries and passed downward at the lingual apex side. Each of the crura possessed its own loop. It can be said conclusively that this detailed investigation of the intrapapillary microvascular architecture in the rat has enabled a morphological classification of the papillae to be made.