Question

Below are the events that occur during continuous propagation of action potential. Select the correct order in which the events occur.

1. Adjacent membrane segment depolarizes.
2. Local current spreads to adjacent voltage gated channel.
3. Threshold is met.
4. Local current develops due to sodium moving in the cytosol.

A) 2,4,3,1
B) 2,4,1,3
C) 4,2,3,1
D) 4,2,1,3
E) 1,4,2,3

Answer 1

The correct sequence for the continuous propagation of an action potential is: local current develops due to sodium moving in the cytosol, local current spreads to adjacent voltage-gated channel, threshold is met, and the adjacent membrane segment depolarizes.

Step-by-step explanation:

Correct Order of Events During Action Potential Propagation

The correct order of events during the continuous propagation of an action potential in a neuron is as follows:

1. Local current develops due to sodium moving in the cytosol.
2. Local current spreads to adjacent voltage-gated channel.
3. Threshold is met.
4. Adjacent membrane segment depolarizes.

When a neuron is stimulated and the membrane potential becomes more positive, reaching a threshold, this causes voltage-gated sodium channels to open. Sodium ions (Na+) enter the cell, causing a local current that depolarizes the membrane segment immediately adjacent to the active zone. As the local current spreads, it opens more sodium channels in the adjacent segment of the membrane, leading to further depolarization. This sequence continues down the length of the axon in a wave-like fashion, resulting in the propagation of the action potential.