THE HEART. 



321 



arterial and venous, in their passage through the heart, follow a course 

 which is, in each case, curvilinear and more or less spiral in direction ; 



Fig. 103. 



RIGHT AURICLE AND VENTRICLE; Auriculo-ventricular Valves closed, Arterial 



Valves open. 



the axes of the currents crossing each other in the right and left cavi- 

 ties of the organ respectively (Fig. 104). The venous blood, received 



Fig. 104. 



COURSE OP BLOOD THROUGH THE HEAKT. a, a. Vena cava, superior and inferior. 

 b. Right ventricle, c. Pulmonary artery, d. Pulmonary vein. e. Left ventricle. /.Aorta. 



by the right auricle from the two venae cavae, passes downward and 

 forward from the auricle into the ventricle. In the body of the right 



