“On the nature of the reflexes controlling the successive movements in the mechanism of deglutition”

Abstract

The entire act of deglutition consists of a series of consecutive movements beginning with the elevation of the mylohyoid muscle of the floor of the mouth, progressing through pharynx and esophagus and terminating with the contraction of the cardia at the entrance of the stomach. The progress of these movements is surprisingly well regulated and stable. Each section of this canal enters into the peristaltic movement invariably at a given interval after the beginning of the swallowing. The time allowed for the entire course differs with each species of animal; it is about 7 seconds for the human being, about four seconds for the dog, and about 2 seconds for the rabbit.

It was early recognized that these stable relations were under the control of a reflex mechanism. That the contractions could not be caused by a direct stimulation of the muscle coat of the esophagus by the passing food was proved by the fact that there is no peristalsis when the vagi are cut. In a series of experiments carried out by Ludwig and Wild at about the middle of the last century, it was found that ligation or transverse section of the esophagus prevents the further progress of the peristalsis to the lower segment. They drew the conclusion that the reflex is of a local nature, that is, that the food or drink while passing the esophagus sends up from each transversed section a sensory impulse which causes a reflex contraction of that section. Some twenty-five years later, however, A. Mosso made similar experiments and obtained opposite results; namely, that after ligating, transverse cutting, and even after removing a whole ring of the esophagus, the peristalsis once begun would appear also in the lower end of the esophagus.