156 



UNCONSCIOUS NERVOUS OPERATIONS 



215. The Right Ventricle occupies the principal part of 

 the forward surface of the heart, but is not a part of the 

 apex. The walls are thicker than those of the auricles 

 and less smooth. From the upper side of the cavity of 

 the ventricle a large opening leads to the great pulmonary 

 artery, while a still larger opening admits the blood from 



Right Auricula-Ventricular 

 Aperture\ 



J^eft Auricula-Ventricular 

 \ Aperture 



Aorta 



Pulmonary 

 Artery 



Semilunar Valves 



.Flaps of Tricuspid 

 Valve 



Tendinous 

 - Cords 



'--^Papillary 

 Muscles 



89. Eight ventricle, cut open to show the structures that 

 regulate the action of the tricuspid valve. 



the right auricle (Fig. 89). The tricuspid valves prevent 

 the return of blood from the ventricle to the auricle. The 

 three main divisions of the valve and three smaller ones 

 are all triangular in shape, and are attached by their bases 

 to a tendinous ring surrounding the opening. The thin- 

 ner edges of the valves are flaps of transparent membrane 



