Animation of two voltage-gated Na⁺ channels in an action potential.

• The animation starts after the Na⁺/K⁺ pump has pumped the Na⁺ out and the K⁺ in. At this point V_m=0 (green color).
• When you click (start), the K⁺ channels allow the K⁺ out, establishing the resting potential (orange color).
• When you click (Start Vm + wave), the wave of depolarization (inidicated by pink color) starts from the left and spreads to the right. As it spreads, the voltage-gated Na⁺ channels open, causing further depolarization, opening more voltage-gated Na⁺ to open, etc.

Key to Symbols used in animation

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Evelyne Tschibelu 2003