THE CIRCULATION 



173 



' ACTION OF 

 THE HEART 



CIRCULATION 



COURSE OF 

 THE BLOOD 



Auricular 

 Contraction 



Ventricular 

 Contraction 



Beating 



Sounds 



In Arteries 



In Capillaries 



In Veins 



f Simultaneous, 

 j Blood forced into ventricles. 

 1 Force not sufficient to cause regurgitation 

 I into the veins. 

 Valves between the auricles and ventricles 



closed. 



Chordto tendinesB tightly stretched. 

 Semilunars forced open. 

 Blood forced into the great arteries. 

 Apex of heart tilted forward against the 



front wall of the chest. 

 From 60 (old age) to 120 (young child) per 



minute. 



Dull sound closure of tricuspid and mitral 



valves, and contraction of ventricles (?). 



Sharp sound sudden closure of semilu- 



nars. -^- 



Followed by a pause. 



Inje.rks (pulsations). 



Very rapid ^ 



Elastic recoil tends to produce a continuous 

 stream in the smaller arteries. 



\Vry slow and uniform. 

 ; (Jreut resistance offered by the capillary 

 [ walls. 



f Much faster than in capillaries. 

 j Not so rapid as iu arteries. 

 ] 'Steady flow. 

 [ Valves prevent backward flow. 



Rjght auricle. 



Right ventricle. 



Pulmon- >T -y nrtiP^ Q 



Lungs (capillary system). 



Pulmonary ^eiqs. 



Left auricle. 



Left ventricle. 



Aorta. 



QajjUlacyjnfitworks in all parts. 



Venae cavae. 



Right auricle. 



Pulmonary Circulation. 



Systemic Circulation. 



