Local Potential Basics
Local potentials are small, graded electrical changes in neurons. They result from ion movement through channels, and unlike action potentials, they're decremental and reversible.
Local vs. Action Potential
While local potentials are graded and can summate, action potentials are all-or-nothing events. Local potentials must reach a threshold to trigger an action potential.
Action Potential Initiation
An action potential begins at the axon hillock. A sufficient local potential here can depolarize the membrane to a critical threshold, leading to the action potential.
Ion Channels' Role
Voltage-gated ion channels are essential for action potentials. They open and close in response to voltage changes, allowing the rapid influx and efflux of ions.
Refractory Periods
After an action potential, the neuron enters a refractory period. This ensures one-way signal propagation and limits the frequency of nerve impulses, thus preventing overlap.
Surprising Neuron Fact
The human brain generates about 20 watts of power, enough to power a low-wattage LED bulb.