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Updated: Jun 19, 2026

Modeling Biological Membranes with Circuit Boards and Measuring Electrical Signals in Axons: Student Laboratory Exercises
Published on: January 18, 2011
TRANSVERSE ELECTRIC IMPEDANCE OF THE SQUID GIANT AXON
1Department of Physiology, College of Physicians and Surgeons, Columbia University, New York, and The Marine Biological Laboratory, Woods Hole, Massachusetts.
Abstract:
The impedance of the excised giant axon from hindmost stellar nerve of Loligo pealii has been measured over the frequency range from 1 to 2500 kilocycles per second. The measurements have been made with the current flow perpendicular to the axis of the axon to permit a relatively simple analysis of the data. It has been found that the axon membrane has a polarization impedance with an average phase angle of 76 degrees and an average capacity of 1.1microf./cm(2) at 1 kilocycle. The direct current resistance of the membrane could not be measured, but was greater than 3 ohm cm.(2) and the average internal specific resistance was four times that of sea water. There was no detectable change in the membrane impedance when the axon lost excitability, but some time later it decreased to zero.
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