THE CIRCULATION 



183 



ACTION OF 

 THE HEART 



Auricular 

 Contraction 



Ventricular- 

 Contraction 



Beating 



Sounds . . 



Simultaneous. 



Blood forced into ventricles. 



Force not sufficient to cause regurgitation 



into the veins. 

 / Valves between the auricles and ventricles 



closed . 



Chordae tendineas tightly stretched. 

 Semilunars forced open. 

 Blood forced into the great arteries. 

 Apex of heart tilted forward against the 



front wall of the chest. 

 From (X) (old age) to 120 (young child ) per 



minute. 

 \ Dull sound closure of tricuxpid and mitral 



valves, and contraction of ventricles (?). 

 Sharp sound sudden closure of semilu- 



nars. 

 Followed by a pause. 



CIRCULATION 



COURSE OF 

 THE BLOOD 



In Arteries 



In Capillaries 



In Veins 



Causes 



In jerks (pulsations) 



Very rapid. 



Elastic recoil tends to produce a continuous 



stream in the smaller arteries. 

 f Very slow and uniform. 

 \ Great resistance offered by the capillary 

 I walls. 



{Much faster than in capillaries. 

 Not so rapid as in arteries. 

 Steady flow. 

 Valves prevent backward flow. 

 ( Heart. 



i Muscular action. 

 I Respiration. 



Right auricle. 

 Right ventricle. 

 Pulmonary arteries 

 Lungs (capillary system). 

 Pulmonary veins. 

 Left auricle. 

 Left ventricle. 

 Aorta. 



j Capillary networks in all parts. 

 Venae cava3. 

 Right auricle. 

 Capillaries of spleen, pancreas, 



stomach, intestines. 

 Portal vein. 

 Capillaries of liver. 

 Hepatic vein. 

 Inferior vena cava. 

 Right auricle. 



Pulmonary Circulation. 



\ Systemic Circulation. 



Portal Circulation. 



