Neuron Transmission: Membrane Potential YouTube Lecture Handouts for NET, IAS, State-SET (KSET, WBSET, MPSET, etc.), GATE, CUET, Olympiads etc.

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Nerve Impulse - 3 Membrane Potential Na-K Pump

Membrane Potential

Neurons – Electrical Charge called membrane potential

Na-K Pump

  • Specialized transport protein in cell membranes
  • Ions: Charged Particles Na+ has missing electron
  • Ion + Protien ⇾ Changes shape of protein
Illustration: Na-K Pump
Illustration: Na-K Pump

Membrane Potential

Resting Potential

Post-Synaptic Potential

Action Potential

Resting Phase (-70 mV)

  • Stable negative charge of inactive neuron
Illustration: Resting Phase (-70 mV)

Red (Na + in) & Orange (K + out)

Illustration: Resting Phase (-70 mV)

Myelin Sheath (Saltatory Conduction – Somersault - Jump)

Illustration: Resting Phase (-70 mV)
Illustration: Resting Phase (-70 mV)

All or Nothing Law

  • Axon either produces action potential or it does not
  • For action potential – Threshold must be reached
  • If not, neuron will not fire
  • Similar to firing of GUN
  • After firing, cannot fire or 1 to 2 millisecond – Absolute Refractory Period
  • Then Relative Refractory Period - Neuron will fire only if stimulus is too strong
Illustration: All or Nothing Law

Manishika