THE UTILIZATION OF FOOD IK ANIMALS 341 



then pumps it through the rest of the body. It is brought 

 back again to the right side of the heart. Each side of the 

 heart consists of two chambers separated by a valve. The 

 auricle is a thin-walled chamber which receives the blood on 



lung 



pulmonary veins 



left auricle 



left ventricle - 

 aorta 



digestive tube 



pulmonary artery 

 lymph vein 



right auricle 

 riijht ventricle 

 caval vtin 



FIG. 161. Diagram of the course of the blood through the body 



its return to the heart. The ventricle is thick-walled and 

 sends the blood out by a powerful contraction. (Trace the 

 course of the arrows in diagram 161.) 



The blood is the great carrier of the body. It takes food 

 from the alimentary canal to every cell in the body, and it 

 also brings oxygen from the lungs to every cell in the body. 



