CIRCULATION OF THE BLOOD. 



529 



FIG. 220. BLOOD-PRESSURE CURVE, DRAWN BY MERCURIAL MANOMETER. (Yeo.) 



0to x = zero line, y to yl = 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 HEIGHTS OF BLOOD PRESSURE 

 IN THE DIFFERENT REGIONS OF THE VESSELS. ( Yeo.) 



H, heart; A. arteries: a. arterioles : r, capillaries: V. small veins; r, large veins: H V, being the 

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

 pressures (approximately) in millimeters of mercury. 



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