On the Nerve Supply of the Pars Pylorica and the Duodenum in Goat and Rabbit

Abstract

In the AUERBACH's plexus in the pars pylorica of goat are found ganglia more often in the very muscle layers than between the muscle layers, and besides ganglia are sometimes found extramuscularly. This situation continues into the proximalmost portion of the duodenum. The ganglia in the MEISSNER's plexus in the pars pylorica and the duodenum of goat are far poorer in development than those in the AUERBACH's plexus. The ganglion cells in the ganglia of both plexuses often enough manifest full multipolarity and are capable of being classified into cells of DOGIEL's Type I and Type II, but are sometimes of young type scarcely having any nerve process, especially often in the MEISSNER's plexus. These findings were nearly reproduced in the pars pylorica and the duodenum of rabbit, but the ganglia and the ganglion cells were found considerably worse developed than in goat.The nerve bundles coming into the pars pylorica and the duodenum consist in many fine vegetative fibres and a far smaller number of medullated sensory fibres. The former come into close relation with the AUERBACH's plexus and the MEISSNER's plexus and in company with the long processes from the ganglion cells of these plexuses, spread into the smooth muscle tissue, the submucosa and the propria mucosae, to end in terminal reticula therein. The latter, the sensory fibres, are found rather scantily in the pars pylorica, but in a considerable number in the duodenum, especially in its proximal half.The medullated sensory fibres of cerebrospinal nature innervating the pars pylorica of goat, after losing their myelin sheaths in the muscularis or the propria mucosae, branch out into 2-6 terminal fibres which spread over some extent, to form simple branched terminations. Most of the terminal fibres show little change in size in their long courses and end sharply among the pyloric glands. These terminations are generally smaller in size than but similar in form to the branched terminations found in the duodenum, so that these terminations in both parts probably have the same function, perhaps concerned with the digestive reflex and in raising alarm in the time of disease in these parts. In the pars pylorica of rabbit also, similar ter minations were observed, but their number as well as their construction were far poorer than those in goat. The above findings are of a rather similar order to those observed in cat (KUTSUZAWA).In the duodenum of goat, I found some large- and medium-sized sensory fibres running through the AUERBACH's plexus into the MEISSNER's plexus, thence into the submucosa filled by duodenal glands or sometimes further through the muscularis to the propria mucosae, to end in branched terminations around the duodenal glands or the intestinal crypts or in the thin connective tissue of the villi. The terminal fibres here spread out over a larger area than in the pars pylorica, but again without showing much change in size, and taking no mentionably wavy courses.The duodenum of rabbit was found to contain a rather larger number of sensory fibres than the pars pylorica, especially in the portion more proximal to the orifice of the ductus choledochus. These fibres are sometimes of large size and form terminations morphologically similar to the wide-spread branched terminations in the duodenum of goat described above. The terminal fibres run wavy courses more often than in goat.In the last place, I must mention the sensory fibres and their terminations found in the distal portion of the ductus choledochus of rabbit, even in a somewhat larger number than in the duodenum. The fibres form branched terminations spreading from the submucosa full of tubular glands resembling the duodenal glands into the subepithelial tissue of the longitudinal mucous folds covered by one-rowed cylindrical epithelium. The terminations are of the same type as the branched terminations in the duodenum, and the terminal fibres cover a rather large area.