THE HEART AND ITS DISSECTION 



129 



veins may be seen on the outer surface of the heart, the main vessels lying in 

 the grooves outside the edges of the middle partition, and in the grooves 

 between the auricles and the ventricles. (See figs. 115 and 116.) 



SUMMABY. 



HEART 



Bight cavity I 

 Left cavity . j 



r Bight auricle 



CAVITIES of 

 the HEABT 



Bight 

 ventricle 



Right auricle \ Between these the tri- 

 Right -ventricle I cuspid valve. 

 Left auricle \ Between these the bicuspid 

 Left ventricle J or mitral valve. 

 Thin irregular walls. 



Vena cava superior from upper 



Vessels - 2 arts ' 



Vena cava inferior from lower 



. parts. 

 Thick walls. 

 Papillary muscles. 

 Chorda tendinea. 

 Three cusps form the tricuspid valve. 



.Right pulmonary 



artery to right Semilunar 



Vessels 





valves J ust 

 belowjunc- 



tion. 



Left auricle 



Vessels 



] Left pulmonary [ 

 I artery to left | 

 ^ lung. 

 Thin irregular walls. 



I Right pulmonary vein from 



right lung. 



1 Left pulmonary vein from left 

 ( lung. 



f Very thick walls. 

 Papillary muscles. 

 Chorda tendinea. 



Two cusps form the bicuspid or mitral 

 Left ventricle ~! valve. 



Vessel The aorta to all parts. 

 Semilunar valves at its origin. 

 Coronary arteries commence just outside 

 L the semilunar valves. 



QUESTIONS ON LESSON XXII. 



1. Describe the pericardium, and the manner in which it envelops the 



heart. 



2. What are arteries, and what are veins 1 Name the great arteries and 



veins connected with the heart, and describe the direction in which the 

 blood flows in each. 



3. How would .you distinguish between the arteries and the veins of the 



heart ? 



4. What are the auricles ? Where are they situated, and what are they like ? 



5. In what respects do the auricles of the heart differ from the ventricles ? 



In what do the ventricles differ from each other ? 



6. Describe the structures which are exposed on opening one of the ven- 



tricles. 



K 



