64 APPLIED PHYSIOLOGY 



10. Mucous membranes contain little pockets of epithelial 



cells, which produce a slippery fluid called mucus. 



11. A collection of pockets or tubes, lined with epithelium, 



which separates a substance from the blood, is a 

 gland. 



12. The saliva is formed in three glands upon each side 



of the face. 



DEMONSTRATIONS 



26. Notice the various movements of the teeth and tongue, lips and 

 cheeks, in chewing. Have one of the pupils open his mouth wide. 

 Show how the soft palate which forms the roof of the mouth can be 

 raised and lowered. Show the sliding doors of the pharynx, which 

 reach up to the soft palate and with it form an arch over the back part 

 of the tongue. Notice the small projection which points downwards 

 from the summit of the arch. This is called the uvula. 



27. Have the pupils swallow slowly. Notice -that the tongue, begin- 

 ning at the tip, is applied to the roof of the mouth until its whole length 

 touches the palate. Notice that when the back part of the throat begins 

 to swallow, the food is beyond the control of the will. Notice that 

 breathing is stopped, for both the nose and windpipe are closed. 



28. Get a tooth and have it sawed in two lengthwise, so as to show 

 the cavity in its interior. Get another, partly decayed, to show how the 

 nerves of the interior are laid bare and exposed to injury. 



29. Procure the lower jaw of a sheep or pig. With a hammer and 

 chisel split open a part of the bone to show how the teeth are set into 

 the bone. 



30. Point out the difference between the skin and the mucous mem- 

 brane of the lips. Notice that the two are directly continuous. Explain 

 that the mucous membrane is really a modified skin, and that anything 

 in the mouth and stomach is really outside the body proper just as it 

 would be if it were held in the closed hand. 



31. Examine a specimen of mucous membrane under the micro- 

 scope, using a power of at least 200 diameters. Notice the layer 

 of epithelial scales covering its outside. Notice the network of fine 

 connective tissue which makes up the main part of the membrane. 

 Notice the glands. They are tubes, but are cut across in the specimen 



