BIPN 100 Lecture Notes - Lecture 4: Conformational Change, Motor Neuron, Skeletal Muscle
Document Summary
This is a brief large change in trans-membrane potential, this is an action potential. And ionic current across membrane, in this case 2 ionic currents. The rising phase depends on the opening of vg sodium channels. When the membrane channels open, the membrane permeability to sodium opens. There is a driving force on sodium at rest, and when channel opens there is a conductance so now there is an ionic current. (-) driving force = driving force is inward for sodium. Any negative driving force is inward on a positively charged ion. A change in total trans-membrane current (added new current), changes membrane potential, and sodium entering the cell -> more positive charge in cell that changes trans-membrane potential and makes it more inside positive. The depolarization that caused the voltage gated sodium channels to open, also causes voltage gated k channels to open. Voltage gated na opens very fast, the kinetics of this conformational change is very fast.