@AK LECTURES you're seriously a life saver man. Keep doing what you do because you are very good at it. I watch a lot of RU-vid videos to try to learn material my professors don't teach well and you have never disappointed me. Better than Kahn academy even in my opinion because you cover one specific topic in high detail with extremely well drawn graphics. 10/10 would smash the subscribe button. This is coming from a guy who normally can't be bothered to drop a like on a video.
Why does it make sense that the valence, z, is in the denominator of the Nernst equation? Specifically, explain intuitively why it makes sense that the equilibrium potential for an ion with valence +2 would be half the magnitude of the equilibrium potential for an ion with valence +1. (For example, K+ has an equilibrium potential of - 84 mV, but an ion X++, with the same intracellular and extracellular concentrations as K+, would have an equilibrium potential of just -42 mV).
happen to have found the dynamic mystery of neuron's resting membrane potential ...as much as you explained how the unique permeability to precise ions constitute in establishing the resting membrane potential (usually -70mV) , what about the large proteins (-vely) charged molecules found inside the neurons ...do they constitute in establishing the -ve resting membrane charge?
very nice explanation. But wouldn't decrease in internal concentration of potassium ions result in higher potential according to the equation. it then doesn't make sense how we get lower value, namely -70mV?
Sir if resting potential is caused due unequal distribution of charge then why resting membrane potential is - 70 as the potassium ion channels wouldnot open up. If it open the definition of resting membrane potential is wrong?????
but if the K+ channels are open and the concentration of K+ drops in the inside (say to 100mM,and outside increases a little, say to 10mM, and i recalculate, i get an even more positive average result (in this case from -18mV close to 0mV). So how comes that my average result in voltage actually should go down to our -70mV in case of leakage and reduction of K+ in the inside??
When talking about inactivation of voltage gated channels, do they inactivate before an ion reaches nernst? Do charges from a type of ion influence the nernst of another ion?
But, what depends if an ionic channel is open or not? When you said that the cell is more permeable to K that it´s mean that Na has less ion channels, or that these Na channels are closed?
There are some major errors in your video: 1. There exist only 1 electric field and therefore potential across the membrane and you can't take averages! 2. The out flux of potassium ions would lead to a depolarisation of the membrane with respect to potassium and actually would increase the membrane potential and not decrease it! 3. The main reason you have a resting potential of -70 mv is that you have three major ions of potassium, sodium and chlorine and they reach an electrochemical equilibrium with a resting potential of -70 mv when the membrane is not permeable to sodium. 4. You equation for the membrane potential is wrong and it has to be in the form ln ([X]_out/[X]_in) 5. The overall potential is calculated by taking all the ions into consideration using ln ([X1]_out + [X2]_out + [X3]_out]/[X1]_in + [X2]_in + [X3]_in)
