Studies on the Autonomic Nervous Terminations in the Alimentary Tract of a Cat

Abstract

A study was made of features of the terminations of vegetative nerve-fibres using the alimentary tubes of adult cats. The specimens observed were impregnated by SUZUKI's silver-method after they were made into frozen sections. The results summarized in the following description are derived from the data regarding the muscle-layer of colon and the mucous layer of stomach.
1. According to the mode of branching, the nerve networks of AUERBACH's plexus can be classified into 5 orders. The network of the 5th order are composed of mere neurofibrils from which fine terminal nerve-fibres come out between smooth muscle fibres. From this finding, it became evident that the nerve-fibres of AUERBACH's plexus innervated the muscle fibres in both circular and longitudinal plates of the muscle-layer of colon.
2. Bundles of nerve-fibres in the alimentary tract are accompanied by the following cells or nuclei, i. e., ganglion-cells, nuclei in leitplasmodium, and intercalated cells. They seem to be innervated in conformity with the function of respective organs.
3. Of a neurofibrilar structure of peripheral nerve-fibres there exist four basic types as follows:
a. Fibres composed of dense neurofibrils with very few anastomosis.
b. Fibres composed of thin neurofibrils with many dot-like swellings and few anastomosis.
c. Fibres composed of thin neurofibrils with varicosity.
d. Fibres composed of thin reticulum of neurofibrils with dot-like swellings.
4. The nerve-cells in MEISSNER's plexus of colon are very often located in groups and occasionally they are found enveloping the ganglion.
5. Bundles of neurofibrils passing through the lamina muscularis mucosae of stomach contain three kinds of neurofibrils as follows:
a. The bundle which independently passes through the muscle-plate, and while sending out fine branches on its passage.
b. The bundle which finds its way with a thin longitudinal bundle of smooth muscle fibres in the mucous layer after forming a network in the innermost part of lamina muscularis.
c. The bundle which passes through lamina muscularis with blood capillaries.
6. In the interspace between the cell-basis and the proper membrane of a fundic gland there exists a fine meshed reticulum of neurofibrils from which very delicate neurofibrils come out ending between gland cells. Intercalated cells are also found in some parts of the gastric glands. Their cytoplasma, which are filled with fine argyrophilic reticula, come from the above mentioned basal reticula which send forth thin processes around adjacent gland cells.