IOO 



THE USES OF FOODS 



Where digestion takes place. If we study the accom- 

 panying diagram of the digestive tract we notice that there 

 are several parts to it : the mouth, with the tongue, teeth, 

 and three pairs of salivary glands, which produce saliva 



in the mouth. Beyond 

 the mouth a smooth 

 muscular tube, known 

 as the gullet, which 

 leads to a bag-like or- 

 . gan, called the stomach. 

 Some people think the 

 stomach is the organ of 

 digestion, but it does 

 only a part of the work 

 of digestion. The stom- 

 ach opens into the small 

 intestine, which in the 

 adult is a much coiled 

 tube about thirty feet 

 in length. In this tube 

 most of the digestion 

 takes place. Into this 

 part of the tube are 

 poured juices from two 

 large glands, the pan- 

 creas and the liver. 

 The wall of the small 

 intestine is thrown into thousands of little projections, called 

 wlli, through which the digested food is absorbed into the 

 blood. The large intestine is the last part of the food tube. 

 Near the junction of the small and the large intestine is a 

 little sac, the vermiform appendix, about which most of you 



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Intestine 



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 Intestine 



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Digestive tract. 



