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I've been looking around and I cannot find the answer to this question.

Biological tissues include muscle, fat, skin, etc. This is for medical tomography applications.

I have tried to settle down to a simple approximation of it (consider tissue as water with some ions) and I have not being able to find it.

Thank you.

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  • $\begingroup$ It depends on what you mean by "ohmic": if you mean "is there a linear relation between voltage and current", the answer is probably "no"; but there is some such relation (possibly highly nonlinear) on general grounds: electric fields will exert force on charges and current will therefore flow. See e.g. electric shock. $\endgroup$
    – NickD
    Commented Aug 28, 2017 at 16:13
  • $\begingroup$ Oh this is for full body electricity, I'm more interested in local effects. Thank you ! Maybe if I use low currents this nonlinearity can be approximated linearly. But first I should know the nonlinear behavior. $\endgroup$
    – pancho
    Commented Aug 28, 2017 at 19:55

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I have some experimental data on this. For years I did a lab exercise with my students in which they measured $I$ as a function of $V$ for their arm. They would put electrode paste at two spots on their skin in order to make the connection. We usually took data in the range from about -6 V to +6 V, but sometimes went to $\pm 12$ V if it didn't cause an unpleasant sensation of being shocked. The results generally showed a non-ohmic relationship that looked like it could have been fit with the form $I=aV+bV^3$ for positive $a$ and $b$. The Omhic approximation would probably be good to about 10% for $|V|<3$ V.

I would guess that dry materials such as bone, ivory, and hair would behave very differently, and that our results were qualitatively similar to what you would get by dipping electrodes in a saline solution.

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  • $\begingroup$ I think this is good enough for what I'm looking. $\endgroup$
    – pancho
    Commented Aug 28, 2017 at 20:43

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