/'/// 77/0 A'. IX. 



219 



auricle, through lh<- auric ulo-veiitricular opening, to the right ventricle. This 

 opening is guarded by the right auriciilo-vcntricular valves. (3) Blood flows 

 I'mm the right ventricle, by the pulmonary artery, to the lungs. This artery is 

 guarded by the pulmonary semiiunar valves. (4) Blood flows from the lungs to 

 the left auricle of the heart by the pulmonary veins. These veins have no valves. 

 (5) Blood passes from the left auricle, by the left auriculo-ventricular opening, 



Left carutid 

 Innominate 



Arch <rf Aorta 

 Vena earn superior 



RIGHT AURICULAR 

 APPENDIX \ 



drifter of vein 

 of Galen \ 



HNULUS OVALIS 



Left tvfn-1'iri'iit 



Right pulmonary artery 

 Jtuctus arteriosut 



s Lfft pulmonary artery 



f" Pulmonary artery 



Pulmonary semiiunar valve* 



LEFT AURICULAR APPENDIX 



Small papillary muscle connected 

 with septum 



. (1) Columna carnea 



3W ' CHORD* TENDINE* 



Anterior papillary 

 muscle 



Left coronary artery 



ANTERIOR SEGMENT OF TRICUSPIO VALVE 



RIGHT SEGMENT Of TRICUSP1D VALVE 



SECTION OF VENTRICULAR WALL 



Vena cava inferior . 



IMC. 154 . ANTERIOR VIKW OF THE RIGHT CHAMUERS OF THE HEART, WITH THE GREAT VESSELS. 



<3) Posterior papil- (2) Columna 

 lary muscle 



to the left ventricle. This opening is guarded by the left auriculo-ventricular 

 valves. (6) Blood passes from the left ventricle through the aorta to all vascu- 

 lar parts of the body. The aorta is guarded by the aortic semiiunar valves. 

 Systole is a term by which contraction of the auricles and ventricles is desig- 

 nated ; diastole is its opposite. The one extrudes, the other draws in, blood. 



The Foetal Circulation. The lungs are essentially organs whose use in 

 distributing the blood for purification begins after birth. Before the product of 



