A STUDY OF BLOOD MANUFACTURE 93 



peritoneum that hold the small intestine, in place is given 

 the name mes'en-ter-y (see Fig. 33). 



Functions of the Small Intestine. In order to understand 

 the structure of this part of our digestive organs, we must 

 bear in mind that one of its principal functions is to soak up or 

 absorb digested food. To accomplish this, the food must be 

 moved along slowly close to the minute blood vessels and 

 other tubes which are to carry off to other parts of the body 



FIG. 33. Diagram of Cross Section of Abdomen. (In reality the larger 

 part of the abdominal cavity is filled with the coils of the intestine.) 



b.v = blood vessels. d.m = muscles of the back. 



m 1 , m 2 , m 8 = three muscle layers of abdominal wall. rues = mesentery. 

 perit = peritoneum. sk = skin. vert = vertebra. 



the liquefied nutrients. We shall soon see the wonderful 

 adaptations of the intestine for this purpose. 



In the intestines, too, important digestive processes are 

 carried on by the juices that come from the liver and pan- 

 creas. The chemical changes in the food brought about by 

 pancreatic juice and bile will be discussed in connection 

 with the organs by which these digestive fluids are secreted. 

 Beneath the peritoneum are layers of circular and longitu- 

 dinal muscle. By their rhythmical contraction the food is 



