Animation 31.1 The Resting Membrane Potential

INTRODUCTION

Neurons process information in the form of electrical signals (nerve impulses or action potentials) that travel along their axons (long extensions of cell membrane). Electrical charges move across the membrane as charged ions, but the cell membranes of most cells, including neurons, are relatively impermeable to charged ions. However, proteins that act as ion channels and ion pumps are embedded in the cell membrane and make it possible for ions to move, or to be moved, selectively across the membrane.

In this animation, we review how ion channels are responsible for a voltage difference (called the resting potential) across the cell membrane of a neuron.

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Textbook Reference: Key Concept 32.3 The Vertebrate Hypothalamus and Pituitary Gland Link the Nervous and Endocrine Systems, p.816

CONCLUSION

When a neuron is at rest, the cell membrane is far more permeable to potassium (K⁺) ions than to other ions present, such as sodium (Na⁺) and chloride (Cl^-). The electrochemical equilibrium that results from the distribution of these ion species across the membrane, together with the relative permeabilities of each ion, is responsible for the –60mV charge that can be measured across the membrane. This charge is called the resting membrane potential.