Ultrastructures of the Sublingual and Interpapillar Surfaces of the Human Tongue.

The fine structures of the sublingual and interpapillar surfaces of the human tongue were examined by light microscopy, and scanning and transmission electron microscopies. After consent, specimens of the normal median area of the tongue were obtained during surgery. The patterns of microridges on the sublingual and interpapillar epithelial surfaces were similar, but the structure of the longitudinal sections of microridges in the sublingual and interpapillar epithelial cells differed. Long microridges with many branches were abundant in the sublingual area, but from the lingual apex to the lingual body, the proportion, height and number of microridge branches of interpapillar epithelial cells gradually decreased. The width of the interpapillar epithelial cell microridges was least in the lingual apex. The differences in microridge shape between the sublingual and interpapillar epithelial cells may be related to differences in retention of mucus, cell stretching and mechanical forces, reflecting the functions of the respective regions.