Some observations on the transport of food in the alimentary canal of the rat

Abstract

Several series of experiments were arranged so as to study in the rat 1) the effect of the degree of the charge of the stomach upon its rate of emptying, and 2) the rate of passage of the food in the empty small intestine. It was observed that the fullness of the stomach had a positive influence on its rate of emptying. In the empty small intestine the transport of the food after the commencement of the meal is very rapid during the first 5 minutes. In this time the food is carried a distance from the pylorus comprising 53—65 % of the length of the small intestine. Five minutes later 65— 78 % of the small intestine contains experimental food. However, the terminal ileum does not appear to be less filled than the other parts of the small intestine. It contains a slimy liquid which has been forced from the »empty» small intestine towards the caecum. Evidently the ileocaecal valve has remained closed. Only after about 1 ½ hours does the food reach the distal end of the small intestine. It is obvious that the rapid filling of the duodenum and jejunum immediately after the beginning of the meal cannot be explained by the classical conception of peristalsis described by Bayliss and Starling. It is remarkable that in the rat the transport of food in the empty small intestine seems to occur at about the same relative rate as in man.