228 



DIGESTION AND ABSORPTION 



intestines. Would any food be forced through? Might fluids 

 pass through in the same way as a sponge absorbs water? 

 Conclusion. In what ways is liquid food absorbed ? 



Problem 197 : To find the pathway of absorbed foods. 



Method. Study the diagram on page 309, Civic Biology; re- 

 member that digested food is within the intestine. Follow the 

 course of sugars and digested proteins as far as the heart. What 

 happens to the blood vessels in the liver? 



NOTE. Sugar is taken from the blood and stored as animal starch (glycogeri) 

 in the liver and muscles. Fat during the process of digestion by the pancreatic 

 juice is split into fatty acids and glycerin and is absorbed as such. In the villi, 

 these fatty acids and glycerin are rebuilt into small fat particles. They pass 

 through the lymph capillaries, called the lacteals, which empty into the thoracic 

 duct and thence into the heart and circulation. 



Conclusion. 1. Write a brief paragraph summarizing the 

 different pathways by which food reaches the heart and general cir- 

 culation. 



2. Complete the following table : 



PROBLEM QUESTIONS 



1. What are the uses of (a) the incisors, (6) the canines, (c) the 

 premolars, and (d) the molars? 



2. How many teeth are there in our first set of teeth? When 

 do they begin to come, and when do they go? 



3. What makes teeth decay? 



4. Why should we clean the teeth night and morning? 



