Question

Read the following statements that describe what happens as an impulse travels. What is the correct order in which the steps occur?

1) The neuron receives a stimulus great enough to start an impulse.
2) Na+ gates close and K+ ions flow back out of the cell restoring the resting potential.
3) Gated K+ and Na+ channels are closed. The inside of the cell is slightly negative compared to the outside.
4) The impulse continues to travel down the axon away from the cell body.
5) Gated Na+ channels open. The net movement of Na+ ions into the cell produces the action potential.

Answer 1

3 1 5 4 2 read action potential ???
first nerve cell is in resting state with more k inside and na outside with a resting membrane potential.
then a electrical impulse greater than threshold potential comes along ....causes na channels to open na enters more into cell and k moves out and action potential occurs ...this is carried forward thru the axon with saltatory conduction depolarisation occuring only in nodes of ranvier the rest of axons membrane being covered with myelin and hence nonpermeable to ions....finally the k moves in and na goes out restoring the resting membrane potential..

Answer 2

1 3 2 5 4