PHYSICAClass 11 Zoology simulations · Neural Control and Coordination
Nerve impulse: the action potential
Stimulate an axon. If the stimulus reaches threshold, Na⁺ rushes in and a full action potential travels along it.
What to notice
The response is all-or-none: below threshold nothing travels; above it the spike is always the same size.
Key relation
Resting ≈ −70 mV → depolarisation (Na⁺ in) → repolarisation (K⁺ out)
Try this
Increase the stimulus slowly. At what value does the impulse fire?
What you can change
- Stimulus strength: 0 to 40 mV
- Threshold depolarisation: 10 to 25 mV
More in Neural Control and Coordination
- Myelinated vs non-myelinated fibres
- Reflex arc: the knee jerk
- Transmission across a chemical synapse
See all Class 11 Zoology simulations or every Physica simulation.