THE RESPIRATORY SYSTEM. 71 



QUESTIONS. 



What is the use of the respiratory system ? 

 What are the chief organs of respiration ? 

 Where are the lungs located ? 

 Describe their structure ? 

 What is the trachea ? 



What vessel brings the blood from the heart to the lungs ? 

 Tell what takes place in the lungs. 



Is the act of breathing performed by voluntary or involun- 

 tary muscles ? 



Why is this a wise provision ? 



What is meant by inspiration ? Describe the process. 

 What is meant by expiration? Describe the process. 

 What is the lining membrane of the chest called ? 

 What is the benefit of full and deep breathing ? 

 What are the consequences of cramping the chest ? 

 What is the effect of exercise on the lungs ? 

 How is the air made impure by breathing ? 

 Tell what you can of the necessity of ventilation. 

 Where are the vocal cords ? 

 How are the sounds of the voice produced ? 

 How is the pitch of the voice varied ? 

 How are the louder tones produced ? 

 What other organs assist in forming the sounds of speech ? 



THE DIGESTIVE SYSTEM. 



Where does the building and repairing material, 

 which is delivered to all parts of the body by the 

 blood, come from ? How is it prepared and how 

 does it find its way into the blood-vessels of the cir- 

 culatory system ? These are some of the physiolog- 

 ical queries which come to us now. 



