THE ABSORPTIVE SYSTEM. 



91 



In concluding our consideration of the 



Suggestions * . 



to the absorptive system, let it be suggested 



Teacher. tliat the Anatomical Aid be constantly 

 referred to. In all topics discussed, it will be an 

 Aid indeed, and the work be made incomparably 



more effective. 



OUTLINE. 



Food is absorbed. 

 It is conveyed to the circulation. 

 WHAT? -J Surplus and worn-out tissues are collected. 



They are renovated and prepared for use, and are 

 again thrown into the blood to be used. 



In the walls of the alimentary canal. 

 In the system at large. 

 WHERE? ^ In the tissue of the skin. 

 In the cells of the lungs. 

 Wherever blood-vessels are found. 



WHY? -| To collect and transfer material. 



QUESTIONS. 

 What is absorption? 

 How do plants illustrate the manner in which food is taken 



from the intestines? 



What is there in plants to correspond with blood in animals? 

 What gives the lining membrane of the intestines its smooth, 



velvet-like appearance ? 

 What do the intestinal villi contain ? 

 Describe their structure. 

 What is the portal vein ? 

 Trace the food absorbed by the veins, from the intestines to 



the heart. 



How is the blood changed in its passage through the liver ? 

 Where is the hepatic vein ? and what is its function ? 

 What are the lacteals ? What is their function ? 

 Of what general system are they a part ? 



