Can someone explain to a retard why the action potential overshoots?

>>8481124
It's due to voltage controlled gates.
As the cell depolarises, these gates become all open and let sodium in and potassium out, leading to hyperpolarisation (the overshoot). It's basically a phase of positive feedback between the gates and membrane polarisation.

>>8481131
Thanks but what causes inward diffusion of sodium to overcome repulsion from the accumulating positive charge?

>>8481124
Khanacademy has pretty good videos about this subject. https://www.khanacademy.org/science/health-and-medicine/nervous-system-and-sensory-infor/neuron-membrane-potentials-2014-03-27T17:58:17.207Z/v/neuron-action-potential-description

>>8481133
Diffusion down a gradient. The 'accumulating positive charge' is negligible.

>>8481232
Thanks senpai. Is there an intuitive proof why it is negligible? And why is only a gradient of sodium relevant shouldn't the concentration of non-sodium things inside be high enough to restrict diffusion?

File: RLC_transient_plot.png (103KB, 1001x805px) Image search: [Google]

103KB, 1001x805px

>>8481124
I'm just an EE with no clue about biology, but it looks like the transient voltage of an RLC circuit. Maybe because the potential gradient acts like a capacitor and when it discharges it oscilates due to some inherent inductance.

>>8481919
Also EE major with very little bio background, I thought the same thing

>>8481957
>>8481919
Nah it's that at all. It's because the voltage-gated channels don't turn off until they sense a minimum positive voltage, and they don't all turn off instantaneously and simultaneously.

>>8481860
The Goldman and Nernst equations will show you why, if you solve them for their respective ions:
they basically show the balance between the forces due to both the electric, and concentration gradients