CIRCULATION AND THE BLOOD SYSTEM 79 



side of the heart? Locate, with the aid of the bristles, the 

 entrance of the pulmonary veins. How many enter the 

 auricle? Find the entrance from the auricle to the ventricle, 

 and the mitral valve which guards this entrance. Does it 

 show chordse tendinse and papillary muscle attachments? 

 How does it differ in shape from the tricuspid? Locate the 

 semilunar valves at the entrance of the aorta. 



Make a careful diagram of the course of circulation through 

 the heart to the lungs and back to the heart and body. 



