106 LABORATORY MANUAL 



A. Walls of the mouth cavity. 



1. How do the walls enclosing the mouth cavity 

 differ from each other ? Note the hard portion or roof 

 of the mouth. How far back does it extend? This is 

 called the hard palate. The softer portion at the back 

 of the mouth is called the soft palate; hanging 

 down from its free border is a conical projection, the 

 uvula. What is its function? 



2. What difference do you observe between the 

 outer and inner covering of the cheeks? What are 

 the characteristics of the inner covering, or mucous 

 membrane? 



B. Salivary glands. 



1. Pull aside with the fingers one corner of the 

 mouth. Find the small elevation on the inside of the 

 cheek. The duct from one of the salivary glands 

 (parotid gland, lying close in front of the ear) opens 

 on this elevation. 



2. Lift the tongue and note the glands (sub-lingual) 

 lying just beneath. The ducts from these glands open 

 in the front of the mouth beneath the tongue. Feel 

 them with the tip of the tongue. 



3. Find the third pair of salivary glands (sub- 

 maxillary) lying beneath the floor of the mouth just 

 behind the sub-lingual near the angle of the jaw. 



C. The tongue. 



What kind of covering has the tongue? Describe 

 the difference between the upper and under surfaces. 

 Can you see any difference in the size, shape, number, 



