A morphometrical observation on the nerve fibers in the human taste bud with an electron microscope (author's transl)

Abstract

The whole thickness of the epithelium of the human circumvallate papillae was dividedtentatively into three portions from its superior surface; upper (UP), middle (MP), and lower portions (LP). The photos of three transverse sections of circumvallate taste bud in one portion, totally nine sections in three portions, were taken with an electron microscope. After making a photomontage connecting nine photos at each level, the number and the area of nerve fibers were observed morphometrically.The results are as follows:1. The numbers of nerve fibers observed were 535 at LP, 272 at MP and 239 at UP. The average numbers in sections were 178.3 at LP, 90.7 at MP and 79.7 at UP. The packing densities were 0.47/μ2 at LP, 0.12/μ2 at MP and 0.10/μ2 at UP.2. The mean values of the area were 0.30μ2 at LP, 0.92μ2 at MP and 1.05μ2 at UP. The size distribution of the area did not distribute even at each portion ranging from 0.01μ2 to 8.23μ2. The areal distribution was not significant under the level of 1 percent by the triserial correlation among LP-MP-UP, but significant under the level of 1 percent by the biserial correlation and critical ratio alnong LP-MP, LP-UP and LP-(MP+UP). Sixty-six percent of the nerve fibers at LP, 29.4 percent at MP and 40.3percent at UP were small than o.20μ2, which indicates characteristic distribution. The result on the significance of the independence of the areal division by χ2-test, when areas were divided into two categories at 0.20μ2 and into four categories at 0.40μ2, 1.80μ2 and 4.00μ2, was the same as that of the areal distribution mentioned above.The nerve process and nerve courses presumed from the results of the present observation are characteristic and support quantitatively the reports previously published by other authors.