CIRCULATION OF THE BLOOD. 



529 



Fig. 220.— Blood-Pressure Curve, drawn by Mercurial Manometer. ( Yeo.) 



to .. = zero line, y to yt = curve with large respiratory waves and small waves of heart impulse. A scale 

 is introduced to show height of pressure in millimeters of mercury. 



Fig. 221.— Diagram showing the Relative Hetghts of Blood Pressure 

 in the Different Regions of the Vessels. ( Yeo.) 



H, heart; A, arteries; a, arterioles; c, capillaries; V, small veins; v, large veins; H V, being the 

 zero line, the pressure is indicated by the elevation of the curve. The numbers to the left give the 

 pressures (approximately) in millimeters of mercury. 



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