Some aspects of human and canine macroscopic pancreas innervation.

Both vagus nerves and the celiac ganglion complex are the main source of the pancreatic gland innervation. In both man and dog there is a distinct difference in the number of fibers ending in the different segments of the gland. In the former, the macroscopic innervation is primarily concentrated in the pancreas head and isthmus. In the latter most of the nerves enter through the upper part of the right limb (uncinate process). Both vagus nerves send direct fibers to the gland but in most of the nerves, that course in general along the different branches of the celiac and mesenteric arteries, the parasympathetic and adrenergic fibers are intermingled. The anterior hepatic plexus, continued down by the gastroduodenal, completes a nervous circle, at the lower edge of the pancreas, with the branches arising from the splenic plexus. In human pancreas most of the nerves, with the exception of the branches given off by the gastroduodenal network, enter the gland by its periphery, either through its superior or inferior border. The gastroduodenal plexus is the pathway for the duodenopancreatic and the duodenogastric arc reflexes and for the "pancreatic type" of pain triggered by some posterior penetrating duodenal ulcers.