C_S_D 4430 Lecture Notes - Lecture 5: Resting Potential, Cell Membrane
Document Summary
The membrane potential, continued 2: permeability vs. conductance. Refers to how easily an ion or other substance can pass through the membrane organic and inorganic anions (negative ions-except cl) cannot pass through the membrane at all. Water, gases, and nutrients can pass through easily. Na+, k+, and cl- pass through, but with some difficulty depending on the state of special protein channels for these ions. Conductance is the electrical equivalent of permeability. it is a number describing the ease with which an ion passes though the cell membrane. Conductance values for the three major ions in the resting neuron are considerably different. K+ and cl- conductance values are fairly high. Conductance can change though the opening and closing of ion-specific channels. It s the controlled manipulation of ion conductance across the plasma membrane that allows neurons to do their work. The varies concentrations and voltage gradients account for almost all of the resting membrane potential.
