Detailed observation of the structure of filiform papillae (FP) and microvasculature of those papillae in Japanese Azuma mole were described. In the anterior and medial regions, FP was cylinder in shape with two processes. In the posterior region, it had a long, sharp conical shape. The microvascular casts showed two types of hairpin-shaped capillary loops on three regions of the tongue. In the anterior and medial regions, the end of the capillary loops were shaped like a spoon. In contrast, in the posterior region, it was knot-like end of capillary loop. Since the shape of capillary loop was more complex in the anterior and medial regions than that in the posterior region, it was speculated that the spoon-like end of capillary loops of the FP in the anterior and medial regions supply nutrients to the filiform papillary cells and may be related to the movement of the tongue during mastication in Japanese Azuma mole.

Summary: In the development of the human mandible, the process of bone calcification, distribution and expression of tenascin-C and -X in the mental symphyseal region are unknown. The purpose of this study was to determine the distribution of these extracellular matrices in the connective tissue around calcified tissues located on the mental symphyseal region of the human fetus during development through histological and radiographical studies.The radiographic density increased from 16 weeks to 24 weeks gestation in all examined regions; in contrast, the diameter of muscle fiber in the suprahyoid muscles (digastric anterior and geniohyoid muscles) inserted into the inner mental symphyseal region increased from 24 weeks gestation. The extracellular matrices (tenascin) were shown to have a different distribution in the mental symphyseal region of the human fetus at each stage. These different distributions of tenascin-C and -X were found around the epithelium and the endomysium of the mental symphyseal region, and affect the specific formation of the mandible during ossification with hyoid muscle development in human fetus.