Neurobiology- Action Potential Grade 11

Action Potential:

  1. Neuron is stimulated. Sodium voltage-gated channels open and the sodium ions float inside, because of the concentration gradient and the electrical gradient. Depolarisation.
  2. Now the charges change. The potassium voltage-gated channels open and the potassium ions exit the neutron, because of the electrical gradient. Repolarisation.
  3. The potassium voltage-channel is open for a bit too long, meaning that more potassium ions exit/leave the neuron, causing a refractory period. Hyperpolarisation.
  4. The sodium-potassium moves the ions back to restore the concentration and back to resting potential.

->Stimulus, local potential, has to be strong enough for a action potential to be generated.
->Threshold: -55 mV has to be reached.
->'All or nothing principle'- a full action potential or it stops after the local potentials.

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