62 ELEMENTARY PHYSIOLOGY. 



What changes in the blood take place in the capillaries? 

 By what large vein is the blood from the lower body 



brought to the heart? 

 By what large vein is the blood from the upper body 



brought to the heart? 

 What prevents the blood from flowing backward from the 



ventricle to the auricle? 

 What is the work of the pulmonary artery? 

 What of the pulmonary veins? 

 Why is the muscle of the left heart extra strong? 

 What is the aorta? 

 Now trace the course of the blood, beginning where it comes 



impure to the right auricle. 

 How many divisions of the circulatory system? 

 Why does the heart send the blood to the lungs? 

 Why through all parts of the body ? 



Why is a large part of the blood carried through the liver? 

 What is meant by the pulse? 

 What is the effect of exercise on the circulation? 

 May exercise become too violent? 

 How is the circulation affected in an unused part of the 



body? 

 What is the best kind of exercise? 



THE RESPIRATORY SYSTEM. 



We have learned that the blood in its course 

 through the body is made quite impure and needs 

 to be repeatedly purified. For this purpose the 

 body is furnished with the respiratory system. The 

 chief organs of this system are the lungs, which lie 

 in the chest, close around the heart. Let us get a 

 clear and accurate idea how these important organs 

 are situated. ( Turn to the body manikin. ) Here is 



