Click, drag and zoom through a fully labeled neuron — then fire an action potential and watch it leap from node to node across the synapse. Free and instant, right in your browser.
UPDATED · 2025 · FREE & PRIVATEA complete myelinated motor neuron rebuilt as a living diagram. Hover to preview, click any of its 13 structures for a dossier, drag and zoom right down into the synaptic cleft — then fire an action potential and watch it leap.
Everything works with a mouse, a finger, or a stylus — nothing to install, nothing to type.
Glide across the neuron and each structure lights up with its name before you commit to anything.
Tap dendrites, myelin, vesicles — anything. Its job, a quick fact, and a smooth zoom-to-part appear in the panel.
Pan across the neuron, then scroll or pinch right into the synaptic cleft — the detail survives the zoom.
Trigger a live action potential and follow it leaping node to node, ending in a neurotransmitter release.
This is exactly what you're watching when you press Fire Impulse — the six stages of a single message crossing one neuron.
Neurotransmitters land on the dendrites, opening ion channels and starting tiny local voltage shifts called graded potentials.
The cell body sums every excitatory and inhibitory input over a few milliseconds. Loud voices, quiet voices — all counted.
At the axon hillock the verdict lands: if the summed voltage crosses threshold, voltage-gated sodium channels snap open. No half-firing.
Sodium rushes in and the membrane voltage flips — the action potential, an all-or-nothing spike that never travels at half strength.
The spike regenerates only at the nodes of Ranvier, leaping between them — saltatory conduction, myelin's whole point.
At the terminal, calcium triggers vesicles to fuse with the membrane and spill neurotransmitters across the synapse to the next cell.
Same spike, wildly different journey. The wrapping decides whether a signal sprints or strolls — tap any row to jump back to the diagram.
Neurons come in many shapes, but nearly all of them fall into one of three jobs. The one in the diagram is drawn as the long-range kind.
Carry messages from your skin, eyes, ears and every other sensor toward the brain and spinal cord. Built long and myelinated for speed — the diagram above is one of these.
Carry commands outward — to muscles, glands and organs. Their single axons can run a full metre from spine to toe without a single break.
The connective tissue of thought: short, dense, wildly branched, linking neurons to other neurons. Over 99% of the neurons in your nervous system are these.
Everything people ask about exploring the neuron — from how exact the diagram is, to why myelin has holes in it, to what that Fire button really does.
Tap a question to unfold it.
Hover any structure to preview its name, then click it to open its dossier — what it does, plus a quick fact. Drag to pan, scroll or pinch to zoom, and press Fire Impulse to watch an action potential travel the full neuron. The quick-select list on the right jumps straight to any part.
No. It is a stylized illustration built for clarity: a real motor neuron has far denser branching, thousands of synapses, and proportions that vary with its job. Every labelled structure is real and sits correctly along the signal's path — the shapes are simplified so each part stays easy to spot, click, and tell apart.
A full action potential journey. The signal sweeps in through the dendrites, is summed at the cell body, crosses threshold at the axon hillock, leaps between the nodes of Ranvier in saltatory conduction, and arrives at the terminal — where vesicles release neurotransmitter molecules across the synaptic cleft to the next cell.
Those gaps are the nodes of Ranvier. Myelin insulates the axon, so the electrical signal can only regenerate at these bare nodes — and regenerating node by node lets it travel up to a hundred times faster than it could crawl along an uninsulated membrane.
It depends on thickness and insulation. Thin unmyelinated fibres manage roughly 0.5 to 2 metres per second, while thick myelinated ones reach 100 to 120 metres per second. That difference is why you snatch your hand off a hot pan before your brain has finished feeling it.
Dendrites are the many-branched inputs: they receive signals and carry them toward the cell body. A neuron has exactly one axon, its output — a single fibre that carries the signal away to the terminals. Many voices in, one voice out.
No. The whole diagram runs in your browser. Nothing you click, zoom, or fire is ever sent to a server, logged, or stored.
Yes. It is completely free with no account, no sign-up, and no limit on how much you explore — on desktop, tablet, and phone alike.