Pyloric Block

MUSCULATURE AND MYENTERIC PLEXUS One of the interesting facts about the physiology of the gastro-intestinal tract is that peristaltic waves coursing over the stomach seem to stop at the pylorus or a few centimeters above it. Many investigators (Joseph and Meltzer,1Wheelon and Thomas,2Alvarez and Mahoney,3Payne and Poulton4and Ivy and Vloedman5) have frequently observed tonus waves in the duodenum as the gastric wave approached the pylorus. At times it seems as if the gastric waves actually jump the pyloric barrier and extend down the duodenum as peristaltic rush waves (Alvarez6). And yet, the best evidence points to the fact that the duodenal waves originate in the first part of the duodenum and are not propagated gastric waves which have jumped the pyloric barrier (Cole7and Alvarez). Why do not the gastric waves go on down the bowel, and why are