A quantitative observation of the human circumvallate taste bud with electron microscope (author's transl)

Abstract

The whole thickness of the epithelium of the human circumvallate papillae was divided tentatively into three portions from its superior surface, upper (UP), middle (MP) and lower portion (LP). Three transverse sections of circuvallate taste bud in each portion, totally nine sections, were observed and photographed with electron microscope. After constructing photomontages from nine sections magnified in about 2×104 and making contour pictures traced on three components of the taste bud, soma, nerve fiber and intercellular space, morphometrical observations were performed by curvimeter and planimeter.The number of somata examined was 255 at LP, 241 at MP and 292 at UP.The number of nerve fibers measured was 535 at LP, 272 at MP and 239 at UP.The results obtained from observations are as follows;1. The number of somata contacting with nerve fibers was 180 at LP, 162 at MP and 152 at UP.2. The average circumference length of the soma was 9.9 /1 at LP, 13.1 /1 at MP and 11.8 μ at UP.3. The average covering ratio of the soma with nerve fibers was 30.7% at LP, 23.7% at MP and 22.8% at UP.4. The average contact number of the soma with nerve fibers was 4.3 at LP, 3.3 at MP and 3.1 at UP.5. The average contact length of the soma with one nerve fiber was 0.8 μ at LP, 1.2 μ at MP and UP.6. The packing density of somata in the taste bud was 0.22/μ2 at LP, 0.11/μ2 at MP and 0.12/μ2 at UP.The quantitative observation of the human taste bud has not been reported up to date, hough many reports on the qualitative observation with electron microscope were seen. In this respect the quantitative morphometrical analysis employed in present study will be useful in the fields of physiology, histology and clinical medicine.