Physlet Illustration: Blood Flow in Arteries

 

Constriction = mm

 

 

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Blood flows in an artery with a partial blockage from left to right in the animation (position is in millimeters and times is in seconds). A blood platelet is shown moving through the artery.  How does the size of the constriction (variable from 2 to 10 mm from each wall) affect the speed of the blood flow?  Positions measured in mm, time in seconds, and pressure in mm of Hg.

Hints:

  1. Measure the speed of the platelet (in mm/s) before of after the constriction by pausing and clicking on the platelet to determine its position at two different times.  
  2. Measure the speed of the platelet while it is in the constricted area using the same technique.  Does the speed increase or decrease?
  3. Adjust the size of the constriction to see if the speed responds appropriately.
  4. How does the constriction affect the blood pressure?  Move the detector to different positions and note the pressure.  
  5. Does the blood pressure obey Bernoulli's equation?  Note: To verify this quantitatively, you will need to convert the pressure to Pascals.

Reference

See Walker, Section 14-7 & 8

Illustration written by Mario Belloni and Modified by Chuck Niederriter