Fill in the correct sequence for generation of Action potential in a neuron
Stimulus ⟶Inflow of Na+ ions ⟶ ______⟶Repolarisation ⟶_________
Transmission of Na+ & K+ Hyperpolarization & RMP
The correct sequence of Action Potential is :
1. Stimulus: A stimulus arrives at a neuron synapse.
2. Inflow of Na+ ions: The permeability of membrane to Na+ is greatly increased at the point of stimulus (rapid influx of Na+) and Na+ enters the neurons through ligand gated channels.
3. Transmission: The influx of Na+ ions causes membrane depolarisation which opens the voltage gated Na+ channels, causing high influx of Na+. Opening of the voltage gated channels causes a positive cascade that is transmitted along the axon. Thus an action potential is generated.
4. Repolarisation: The depolarisation of membrane during action potential causes opening of voltage gated K+ channels and a cascade efflux of K+ ions. Meanwhile the voltage gated Na+ channels close. These two processes together causes repolarization of the neuron membrane.
5. Hyperpolarisation and RMP: The voltage gated K+ channels begin to close as the membrane potential reach the resting state. However, their activity causes a slight dip below the resting membrane state, and is called hyperpolarisation. And although there is slight dip in the membrane potential soon after an action potential, the resting channels (leakage channels) ensures that the resting membrane potential is regained soon.