CHAPTER XXXVIII 

 NUTRITION 



Vocabulary 



Nutrition, all processes concerned with building up tissue. 



Alimentary, pertaining to food or nutrition. 



Fallacy, a mistaken idea. 



Distended, swelled up or expanded. 



Lacteals, lymph capillaries of the intestine which absorb fat. 



Someone has said, " We live, not on what we eat, but on what 

 we digest." Food, even after cooking, is not usually in condition 

 to be made into tissue or to furnish energy. 



Digestion produces two important changes in foods. First, it 

 makes them soluble to allow transfer by osmosis; second, it changes 

 them chemically to permit them to be assimilated. These changes 

 are brought about in two ways, first, mechanically by the teeth, 

 the motion of the stomach, and intestinal walls, second, chemically 

 by active substances in the digestive fluids, called enzymes or 

 ferments. The latter are the more important means of digestion; 

 there are several kinds, each acting on a particular foodstuff and 

 each secreted by different glands in various parts of the digestive 

 tract. They will be referred to later when these different regions 

 are studied. 



Digestive Organs. The digestive tract or alimentary canal is 

 practically a continuous tube with many glands opening into it to 

 furnish digestive fluids, also with a rich blood supply to provide 

 for its activities and to remove digested foods. This food tube 

 consists of three general regions whose structure and functions will 

 be studied in order, 



1. The mouth 



2. The gullet and stomach 



3. The intestines. 



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