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ELEMENTARY PHYSIOLOGY 



QUESTIONS ON LESSON XXXVI. 



1. Describe the structure of the outer ear, and explain the uses of its parts. 



2. What is the drum of the ear? Persons are sometimes rendered permanently 



deaf by a violent explosion. Explain how this happens. 



3. Describe the arrangement and uses of the parts of the middle ear. 



4. Write what you know about the structure and functions of the inner ear. 



5. A person may be deaf although the ear is perfect in all its parts. Explain 



this. 



6. In what way does a vibrating body produce the sensation of hearing ? 



LESSON XXXVII. 



THE VOICE. 



THE organ of voice is the larynx, which is a modification of the 

 upper portion of the trachea. It consists of a cartilaginous frame- 



Fig. 213. Front view of the Larynx. 



i, hyoid bone ; 2, thyroid cartilage ; 3, cricoid ; 4, first cartilaginous ring of the trachea ; 

 5, membrane ; 6, ligaments 



work, the parts of which are movable on each other, the motion 

 being produced by the contraction of various muscles. The 



