DIGESTION OF FOOD IN THE MOUTH 6$ 



and appear as circles lined with large cells. Explain that the cells 

 of the glands produce the mucus. 



32. Have a boy open his mouth and raise his tongue upward and 

 backward. With a handkerchief wipe dry the space between the tongue 

 and teeth. In a moment a drop of water will collect between the small 

 projections near the tongue. Move the tongue slightly, and notice 

 that the liquid flows in a tiny stream. Explain that this is the saliva 

 flowing from the sublingual gland. 



33. Chew a piece of white bread. After a little, notice that it has a 

 sweetish taste. Explain that the sweetness is due to the action of the 

 ptyalin of the saliva in changing the starch to sugar. 



34. While a horse or a cow is drinking, notice the peristalsis of the 

 esophagus along its neck as it swallows each mouthful. 



REVIEW TOPICS 



1. Define food and name the five classes. 



2. Tell what change each must undergo in order to enter 



the body. 



3. Tell what effect cooking has upon each class of food. 



4. Discuss the different ways of cooking. 



5. Give the parts of the alimentary canal. 



6. Describe the mouth. 



7. Describe the jaws and teeth. 



8. Tell how the teeth are commonly injured, and how to 



preserve them. 



9. Describe the cheeks , lips, and tongue. 



10. Describe a mucous membrane. 



1 1 . Define a gland. 



12. Describe a salivary gland. 



13. Describe the use and appearance of saliva. 



14. Describe mastication. 



15. Describe the pharynx. 



1 6. Describe swallowing. 



1 7. Describe peristalsis. 



OV. PHYSIOL. 5 



