The circuit in Fig. 2 is a minimal representation of the membrane. It is important to note that this representation refers to a membrane element of very small dimensions, such that the potential could be considered constant along each side of the membrane. This is only true if the element is made infinitesimally small bacause any finite size may not be isopotential due to the electrical resistance of the medium and the geometry of the axon. As we will see below, in the case of the axon we will have to locate this basic circuit of the membrane element in the cylindrical geometry of the axon which will make the final circuit quite complicated. But before incorporating the geometry, we can study the basic properties of our elemental circuit which will be extremely useful in understanding the electrical behavior of the elementary unit that constitutes the axonal membrane.
V is the membrane potential and E e is the reversal potential for that pathway.
There are several types of conductance and their classification is done according to the type of channel involved. Simulation of the membrane potential using the Equivalent Circuit Program . In this section, we will study the currents through the different ionic pathways and the resulting voltage across the membrane. The conventions will be that the inside of the membrane faces down and all the voltages will be referred to the outside. For example, if the membrane potential is -80 mV it means that the inside is negative with respect to the outside.