Building the neuron…
Axon hillock voltage
−70mV
Resting. K⁺ leak channels keep the inside negative.
−90−40
Na⁺ channelsClosedOpenInactivatedK⁺Open
Na⁺K⁺Ca²⁺Neurotransmitterslowed ~1,000×
Mimage · myelinated
A skipping stone
The signal touches down only at the nodes and skips the stretches between.
Inside vs. outside the cell
−70mV
Na⁺K⁺Cl⁻Large anions (A⁻)O₂ / CO₂
BUMP · tap a shape
Glowing dots show which way the signal travels in each shape. In pseudounipolar neurons it skips the cell body entirely.