Variations in the resistivity of blood can give valuable clues to changes in the blood's viscosity and other properties. The resistivity is measured by applying a small potential difference and measuring the current. Suppose a medical device attaches electrodes into a 1.5-mm-diameter vein at two points 5.0cm apart. What is the blood resistivity if a 8.6V potential difference causes a 230 uA current through the blood in the vein?