Action Potential

Voltage Dependent K+ Channel

Simplified Voltage Dependent Na+ Channel

K+ vs Na+ Channels closed-open-inactivated (C-O-I) model

Hodgkin Huxley Model Voltage Clamp Experiments

m gates (Na+)

h gates

n gates (K+)

Resting Potential

Closed

Open

Closed

Depolarization

Open

Open

Closed

Repolarization refractory

Open

Closed

Open

Hyperpolarization refractory

Closed

Closed

Open

Voltage Dependent Ca++ Channels cause increased [Ca++] in cell