170 ANATOMY AND PHYSIOLOGY FOR NURSES 



Peristalsis is the peculiar worm-like motion of the 

 intestines, by means of which its contents are kept in mo- 

 tion and become mixed with the digestive fluids. It is 

 produced by a compressing action of the circular fibers 

 combining with a shortening action of the longitudinal 

 ones. 



Besides the organs just described as being concerned in 

 the nutrition of the body, we will consider here those 

 structures whose function is the absorption of the digested 



FIG. 87. Mucous membrane of the jejunum : i, Payer's patch; 2, its 

 border; 3, solitary follicles; 4, 4, valvulae conniventes (Testut). 



food. These are the lymphatics of the small intestine, 

 known as the lacteals, the villi, and the thoracic duct. 

 (See p. 175.) Of these, the villi have already been 

 described. 



Intestinal digestion is an important and complex 

 function, requiring several important secretions namely, 

 the pancreatic juice, the bile, and the intestinal juice, the 

 first two of which are the most important. They mingle 

 together in the small intestine and act upon the food, not 

 in succession, but simultaneously. 



