The theory of impedance in biological systems

The basic relations of impedance as they pertain to biological systems is slowly varying electric fields are developed. One of the boundary conditions for the quasi-steady state is derived in terms of impedance rather than the limiting case of resistance. Then, given a complete schedule of conditions, the equation of Maxwell for a single membrane-covered sphere is derived in terms of impedance. Cole's relations are then obtained for a thin membrane. The analysis is extended to obtain Cole's relations for a suspension of spheres and alternative boundary conditions are suggested to remove ambiguities in Cole's work. A similar procedure is then applied to a membrane-covered cylinder and a flat sheet with membranous walls. Equations are also derived for experimental systems using electrodes with spherical or cylindrical symmetry.