The Effect of Different Conductivities

In the two-compartment, constant length, parallel cylinder model analyzed previously, the conductivities in the inner and outer cylinders were considered equal. Different conductivities will of course also change G. With a conductivity at of tissue outer cylinder and Gb of blood in inner cylinder, and with constant geometry, the conductance is found from G = aA/L  

Equation 10.6 is not really a plethysmographic equation when the assumption is that no geometrical change shall occur. However, it relates to flow systems with a varying conductivity of the passing liquid, and flow with time is volume. 

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