[Theory of a cable with an irregular cross section]

We proposed an equation of 1D-cable with irregular and alternating shape of cross-section. This equation differs from an ordinary one for the regular cylinder by the generalized definition of electrotonic parameters. The theory is illustrated for the cable with elliptic and alternating sections. The described theory may be useful when defining electrotonic parameters from experimental values. The theory predicts that the commonly estimated values of electrotonic length constant might be higher and membrane's capacity (-)-lower than the real values. Electrotonic parameters (length constant, time constant, characteristic resistance) may be used more successfully than electric parameters of a biological cable (membrane and cytoplasm resistance, membrane capacity).