Question

Select all of the following that are true about a neuron’s function.

1.An action potential occurs if the membrane potential exceeds the threshold potential.

2.A neuron expends no energy while it maintains a resting potential.

3.When the neuron receives a stimulus, sodium ions begin to rush out of the axon.

4.When threshold potential is reached, sodium channels all along the axon open up at once.

5.An axon maintains a positive charge during rest.

6.During the peak of an action potential, more sodium ions are found inside the axon than when it is at resting potential.

7.During an action potential in one section of an axon, sodium channels first open, then delayed potassium channels open and sodium channels close.

Answer 1

1.An action potential occurs if the membrane potential exceeds the threshold potential (TRUE).

2.A neuron expends no energy while it maintains a resting potential (TRUE).

3.When the neuron receives a stimulus, sodium ions begin to rush out of the axon (FALSE).

Following an above threshold stimulus, sodium gated channel proteins open and sodium ions rush from the outside of the axomembrane to the inside.

4.When threshold potential is reached, sodium channels all along the axon open up at once (FALSE).

The sodium ion channels open like a wave traveling from cell body towards the axonal terminal

5.An axon maintains a positive charge during rest (FALSE).

Membrane potential is negative (–70 mV)

6.During the peak of an action potential, more sodium ions are found inside the axon than when it is at resting potential (TRUE).

Since more Na+ ions flow into the axon at this time the membrane potential willl be more positive

7.During an action potential in one section of an axon, sodium channels first open, then delayed potassium channels open and sodium channels close (TRUE).