Three zoom levels. One nervous system.
Start with the whole body — brain, spinal cord and the nerves running to every limb. Zoom into a single neuron to take it apart, then dive deeper still, into the synapse where one neuron hands a signal to the next.
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Three jobs, three kinds of neuron.
Sensory neurons carry signals in from the body, motor neurons carry commands back out to muscles, and interneurons stitch the two together inside the CNS — and make up almost every neuron in your brain. Tap a row to open that neuron in the model.
Four moves and you've read the system.
Everything runs locally in your browser — nothing to install, nothing uploaded, nothing stored.
Pick your zoom
Start at the full body for the whole nervous system, dive into a single neuron to take it apart, then drop into the synapse to see the chemical handoff between two cells.
Drag, pan & zoom
Drag to pan around the specimen, scroll or pinch to zoom from the whole body down to individual synaptic vesicles, and tap SPIN to rotate the model in 3D.
Click any part
Every structure opens a dossier: its full name, what it does, and a quick fact. Use the part index on the right to jump straight to anything you haven't explored yet.
Fire a signal
Switch on SIGNAL to watch nerve impulses sweep from your fingertips to your brain and back, hop along a myelinated axon, or trigger vesicles to release neurotransmitters.
The nervous system, measured.
The most electrically alive tissue in the body — these are the numbers it keeps to.
The brain in figures
Your brain holds roughly 86 billion neurons, joined by an estimated 100 trillion synapses — about a thousand connections per neuron, all packed into 1.4 kilograms of tissue.
Signal speed
The slowest nerve fibres crawl at the speed of a stroll; the fastest — wrapped in thick myelin — carry signals at 432 kilometres per hour, fast enough to outpace a sports car.
The synaptic delay
It takes about one millisecond for a signal to cross a single synapse, and a typical neuron can fire several hundred times per second — a relay race run at chemical speed.
Things people ask.
Everything about how the model behaves, how honest the drawing is, and what it saves (nothing).
Still stuck? Write to us — we read everything.
How do I use the interactive nervous system model?+
Pick a view — the full body, a single neuron, or a synapse close-up. Drag to pan, scroll or pinch to zoom, and tap any structure to open its dossier. Switch on the signal animation to watch nerve impulses travel from your fingertips all the way to the brain.
Is this nervous system model anatomically exact?+
No. It's a stylized, idealized diagram built so every part is easy to see, click and tell apart. Real nervous systems are far more densely packed, with billions of neurons and trillions of synapses — no flat diagram can show that.
What are the three main kinds of neurons?+
Sensory neurons carry signals from the body into the central nervous system, motor neurons carry commands back out to muscles and glands, and interneurons connect neurons to one another inside the CNS — they make up over 99% of your brain.
What's the difference between the body view, neuron view and synapse view?+
The body view shows the whole nervous system — brain, spinal cord and peripheral nerves. The neuron view zooms in on a single nerve cell, showing dendrites, the cell body, the myelinated axon and terminals. The synapse view zooms further in, to the gap where one neuron hands a signal to the next.
Why is the axon wrapped in myelin?+
Myelin is a fatty sheath laid down by glial cells. It insulates the axon and lets the signal leap from gap to gap — the nodes of Ranvier — instead of travelling continuously. This saltatory conduction can boost signal speed up to 50 times.
What does the signal animation show?+
It shows nerve impulses — action potentials — travelling along axons and nerves. In the body view they sweep from the limbs toward the brain and back. In the neuron view they hop along the axon. In the synapse view they trigger vesicles to release neurotransmitters across the cleft.
Does the tool save or upload anything?+
No. The model runs entirely in your browser. Nothing you click, drag, or select is ever sent to a server, logged, or stored.
Can I use this on my phone or tablet?+
Yes. One finger pans, pinching zooms, and tapping selects — so the whole model works the same with touch as it does with a mouse.
Is this interactive nervous system model free to use?+
Yes, it's completely free with no account, no sign-up, and no limit on how much you explore.