TONGUE AND TASTE NOSE AND SMELL 



2OI 



SUMMARY. 



TONGUE 



TASTE 



SENSE OF 

 SMELL 



A muscular organ. 

 Covered with mucous membrane. 



{Smooth and thin on under surface. 

 Raised into numerous papilla on the uppei 

 snrfarp. 



Mucous mem- 

 brane 



surface. 

 Filiform - \ ? lon .g ated and pointed. 



I Smallest and most numerous. 

 , Resembling certain fungi in 



form. 



Fungiform -j Larger than the filiform. 



Papillae . . _j j Distinguished by their deep 



1 red colour. 



(The largest. 

 Arranged in the form of the 

 letter V. 

 At the back of the tongue. 

 Surrounded by a wall or ram- 

 part. 



/ Glosso- j Supplies the back of the 

 Nerves . . J pharyngeal 1 tongue and palate. 



1 Fifth pair \ Su PP lies the fore portion of 

 I the tongue. 



Both pairs of nerves probably concerned. 



Substance to be tasted must be soluble. 



The irritation of the sensory nerves must be transmitted to 



the brain. 

 Sweet and saline tastes perceived chiefly by the tip of the 



tongue. 



Bitter tastes at the back part of the tongue, acid at the edge. 

 Closely associated with the senses of touch and smell. 



Organ 



Conditions 



The mucous membrane of the ethmoidal 

 portion of the nasal cavities. 



Air must enter the ethmoidal cavities. 



Particles of the odorous substance must 

 come into contact with the olfactory fila- 

 ments. 



The irritation thus produced must be trans- 

 mitted to the brain. 



QUESTIONS ON LESSON XXXIV. 



1. Describe the general structure and uses of the tongue. 



2. How does the mucous membrane of the tongue differ from that of the 



other parts of the mouth ? 



3. Describe the general form and arrangement of the different kinds of papillae 



on the surface of the tongue. Of what use are these papillae ? 



4. From what sources does the tongue receive its nerve supply ? 



5. What is the organ of taste ? What are the conditions necessary for the 



production of the sensation called taste ? 



6. How do the different portions of the mucous membrane of the tongue 



differ with regard to the sensations they produce ? 



