Interactive anatomy and physiology labs. Each lab runs entirely in your browser: no install, no account, nothing stored. Click a preview or its launch button to open the lab in a new tab.

Twitch Lab — Action Potentials and the Sliding Filament Model

Fire an action potential on a live oscilloscope and find threshold, test the refractory period with double pulses, and block Na⁺ or K⁺ channels. Then follow the signal through excitation–contraction coupling to the calcium stores, and watch myosin heads walk the thin filaments of one sarcomere. Students measure which bands shrink, see why the A band never changes, and lock the muscle in rigor by removing ATP.

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Before you start

Every lab opens in a new tab and runs entirely inside your browser. Nothing is uploaded, nothing is stored, and no account is needed. They work on laptops, Chromebooks and tablets.