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For Students · Cardiac Action Potential

Cardiac Action Potential for a neuron firing

Built for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition. Simulate a neuron firing live below — adjust the inputs and watch it respond, right in your browser.

Cardiac Action PotentialLive

the electrical heartbeat

Controls

Presets

Heart rate (bpm)

Plateau duration

Upstroke amplitude (mV)

Each heartbeat is an electrical wave: a fast sodium upstroke, a long calcium plateau unique to heart cells, then potassium repolarization. That plateau keeps the muscle contracted long enough to pump — and its length sets the refractory period. Educational tool, not medical advice.

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Data Inspector

Cycle length857 ms

Action-potential duration343 ms

Peak potential+20 mV

Governing equation

C_{m} \frac{d V}{d t} = - I_{i o n}, \frac{d V}{d t}_{ma x} = \frac{110 mV}{10 ms} = 11 mV/ms

Reading this result: The plateau holds the cell near 0 mV for ~343 ms — the calcium phase unique to heart muscle that keeps it contracted long enough to pump before potassium repolarizes it.

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Frequently asked questions

Is this good for students?: Yes — this version of "Cardiac Action Potential for a neuron firing" is framed for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.