2.9.2 Connecting electricity and thermodynamics

The injected ions suddenly act on the elastic membrane as an ”impulse force”, so the membrane (and the incompressible electrolyte it contains) performs a damped oscillation. Given that the resultant of the above mentioned electrical thermodynamic, and constraint forces points toward the AIS, the ions will move with the corresponding Stokes-Einstein speed toward the AIS. However, $F_{Wall}$ is an oscillating force that changes its direction and may be larger than the other forces. The electrical and thermodynamic forces would essentially produce a simple discharge, with having only one current direction. However, the damped oscillation has also a negative phase. In a thermodynamic view, the membrane ”sucks back” the electrolyte containing the ions. In the electrical view, the direction of the ion stream (aka current) changes to the opposite, causing the ’capacitive current’ to change the sign of the resultant current (the neuronal membrane can be modeled as a condenser). In physiological view, polarization, depolarization and hyperpolarization take place. As the model clearly suggests, all ions can be likely $K^{+}$ and $N{a}^{+}$ ions, the question is only their proportion.