My question is very simple: why is it sufficient for a very few ions (such as 1 in 100000 K+) to move across the membrane to generate a remarkable variation in the membrane potential (like a change of 100mV) ??
I took the examples from my university textbook, which, though, doesn't explain the reason behind this statement. Is it because during this event the permeability changes so dramatically that the number of ions doesn't have to be so big?
Can someone help me? Thank you!