Neuron – action potential and nerve impulse conduction

BiologyHuman & Animal PhysiologyAges 16–17

Stimulate a neuron and watch the nerve impulse travel along the axon. Drag the circle to choose an observation point: the membrane there is magnified to show Na⁺ and K⁺ ions, voltage-gated Na⁺ and K⁺ channels opening and closing, leak channels and the Na⁺–K⁺ pump, while a membrane potential graph (mV against ms) records depolarization, overshoot, repolarization and hyperpolarization. Change the stimulus strength to find the threshold and the all-or-none law, stimulate twice in quick succession to see the refractory period, show ions, charges, concentrations and conductances, and pause, step, slow down or speed up. The potential is computed with the Hodgkin–Huxley model and conduction with the cable equation. Based on the "Neuron" simulation by PhET Interactive Simulations, University of Colorado Boulder (CC BY 4.0); rewritten.

Lesson: Nerve impulses and the nervous system