The Activities of the Intestinal Mucosal Motor Mechanism

Much has been writ’tcn about the motor activities of the intestinal tract. A survey of the literature shows that with a few exceptions these writings have been based upon experiments and observations involving only the outer, the circular and longitudinal muscles of the intestine. Little attention has been given to the activities of the muscularis mucosae. Inasmuch as in all higher animals this musculature is well developed, it would seem necessary to assume that it manifests some sort of activity and contributes an essential role to the normal physiology of the small intestine. At this point it is well to recall that some of the fibers of the muscularis mucosae extend into the villi, consequently mucosal motor activities in the intestine would imply movement of the mucosa as a whole, or in limited areas, and also movement of the individual villi. A number of earlier workers have reported observations on movements of the intestinal mucosa. Lacauchie (,I) observed a shortening of the villi after death. Gruby and Delafond (2) observed shortening, lengthening and lateral movement in the living animal. Brueke (3) was among the earlier students of the musculature of the villi and ascribed changes in shape and position in them to muscular contraction and relaxation. Exner (4) studied the reactions of the intestinal mucosa to mechanical stimulation and found it to respond sharply to such a procedure. Gunn and Underhill (5) recorded and studied the movements of the mucosa of the cat’s small intestine, using strips from which the outer musculature had been removed. They were able to record a definite rhythmical movement. Hambleton (6) observed, by using a binocular microscope and watching lighted fields of intestinal mucosa in intact animals, shortening, lengthening and lateral movement of the villi. The present study was undertaken for the purpose of inquiring more fully into the types and varieties of movement manifested by the mucosa