Can someone explain how repolarization/depolarization of ions works in the nerve cells?


I’m really confused about polarization and can’t for the life of me get it to make sense.

In: Biology

Do you know how neurons(nerve cells) are build?

[Some information about the structure of a nerve cell](

When there is a pulse (information) transmitted to one cell to another cell, it will be done through the Axon terminal (Cell A) towards a dendrite (Cell B).

Between these two is a small area filled with “gas” that is called chemical synapses that takes the pulse(or signal) through small ions towards the other side.

When the pulse is transmitted, it will “climb” the Axon to get to the end of the axon (terms can be different (Axon hillock)).

Neurons have to go through a so called Action potential, which is needed to transmit information from your organ cells (muscles, skin etc.) to your brain or vice versa.

This Action Potential happens at the axon hillock, which will be triggered when the incoming pulse is strong enough. It only needs to go over a certain line, so there wouldn’t be a overload of signals and as such information (e.x. after holding something light for a very long time, you won’t really notice it if you don’t move your hand).

After hitting the certain line (around -50 mV), the next phase, the depolarization, is triggered, which tries to change the membrane potential postive by “exchanging” positive with more positive ions. That way the mebran potential can rise to up to (~) +40 mV (also called Overshoot).

Because the depolarization changes the membran potential and increases the difference between intracellular and extracellular space, the Redepolarisation will take effect, which tries to reduce the positivity of the intracellular space (which was done by the Depolarisation), to restore the “normal” potential. (You can compare this as if you would breath out completely, your body naturally wants to inhale some air to not crush your lungs because you created a vacuum). The membrane potential goes into the negative.

After this is the Hyperpolarisation. If you want me to go into details and give you accurate information, then please notify me again.

One thing that I didn’t explain were ion canals and pumps.