Describes how changing the permeability of the neuron and changing the number of sodium/potassium pumps can affect the resting membrane potential and cause either depolarization or hyperpolarization.
Great explanation, subscribed. Would be great if you could just clear up a few doubts for me. If there are little or no leak channels for Sodium, how does the concentration of Calcium affect the sodium channels? Or rather which sodium channels do they affect? It can't be the voltage-gated channels right? If I'm not mistaken they only respond to membrane depolarization. Secondly how does hyponatremia or hypernatremia affect the generation of action potential? When the membrane depolarises, the activation gate of the sodium channel opens but in the case of hyponatremia, the concentration gradient becomes lesser, meaning the driving force on the sodium ions lessens. Would this in any way affect the generation of the action potential? For instance, increasing the threshold potential (from -70 to -50 for example)?
It’s the voltage gated channels - yes they are mostly just for the action potential but calcium levels affect them as described and they do affect resting membrane potential. It’s not a hard and fast rule that sodium voltage gates only are important for the action potential. They can also affect the resting membrane potential.
For the second part of your question, yes you are correct, the amount of sodium in the ECF does affect the height of the action potential. If there is less sodium in the ECF the height of the action potential is lower.
Please , i have a question . I want to know how does hyperkalemia affect repolarization ? . Does it will prevent repolarization because chemical gradient will decrease in hyperkalemia and that will slow Potassium efflux and then repolarization ? Plz , answer me .
The depolarization of the cell in the case of Na+/K+ ATPase dysfunction, is that due to intracellular Na+ and Ca2+ ion accumulation or the decrease K+ ion intracellularly?
Decreasing activity of the Na+/K+ pump decreases K+ inside the cell, decreasing the chemical gradient for K+. (Decreases the potential for the positive ion K+ to leave the cell, making the inside more positive which is depolarization)
@@physiopathopharmaco4190 i know that...but the fact is that hyperkalemia is associated with sodium channels being stuck at inactivation state n thereby cells become less excited eventually..i m looking for a reason to that😔
@@dr.saadatnazir6871 that is because the cells are unable or less likely to reach a hyperpolarized state during repolarization d/t increased equillibrium potentials. Sodium channels (specific subtypes) are unique in that they become reactivated with hyperpolarization. Therefore, no hyperpolarization means Na+ channels are stuck in their closed/inactivated state.
Can't you argue that having more positive ions in the ECF (ie hyperkalemia) will cause the difference between the compartments to be greater, ie more polarized?
