Question

Which one of the following is the correct sequence of events that correlates to the sequence of events of a nerve impulse:

1. the membrane becomes depolarized
2. sodium channels open and sodium ions diffuse inward
3. the membrane becomes repolarized
4. potassium channels open and potassium ions diffuse outward while sodium is actively transported out of the cell

Answer 1

The appropriate sequence for a nerve impulse is depolarization due to sodium ions entering the cell through sodium channels, followed by repolarization as potassium channels open and potassium ions leave the cell.

Step-by-step explanation:

The correct sequence of events during the transmission of a nerve impulse is as follows:

1. Neuronal membrane depolarization initiated by the opening of sodium channels.
2. Sodium ions (Na+) rush into the neuron as a result of these channels opening.
3. The membrane becomes depolarized as the interior becomes less negative.
4. Potassium channels open, allowing potassium ions (K+) to diffuse out of the neuron.
5. Sodium ions are actively transported out of the cell while the aforementioned channels are open, contributing to repolarization.

Therefore, the correct sequence that correlates with the sequence of events of a nerve impulse is:

1. The membrane becomes depolarized.
2. Sodium channels open and sodium ions diffuse inward.
3. Potassium channels open and potassium ions diffuse outward while sodium is actively transported out of the cell.
4. The membrane becomes repolarized.