118 ABSORPTION 



ready to be taken up into the blood and carried to every 

 organ. 



12. Absorption from the Small Intestine. As the chyle 

 passes along, it is gradually absorbed by the mucous 

 membrane, which is specially adapted to fulfil this duty. 

 Instead of being nearly smooth like the mucous mem- 

 brane lining the mouth, it is raised up into numerous 

 folds (Fig. 33) which greatly increase the extent of its 

 surface; and thus it is enabled to absorb more and 

 quicker than if it was stretched smooth and flat. The 



FIG. 33. A portion of the small intestine opened to show the folds of its mucous 

 membrane. 



pockets or hollows between the folds also have their 

 use. The chyle collects in them and is thus prevented 

 from passing along faster than it can be absorbed. 



13. The Villi of the Small Intestine. All over the mucous 

 membrane of the small intestine, both on its folds and 

 between them, are tiny elevations, which stand up like 

 the pile on velvet. Each elevation is a villus, and, small 

 though it is, contains two sets of tubes or vessels. One 



12. For what is the mucous membrane of the small intestine 

 specially adapted? How is the extent of the surface of its mucous 

 membrane increased? Use of these folds ? Of the hollows between 

 them? 



13. Describe the surface of the mucous membrane of the small in- 

 testine. What is a villus ? What does each villus contain ? Use of 

 the villi ? Where does the chyle absorbed by them go ? 



