16. Which of the following statements are accurate?

A. Sodium diffusing into a neuron will cause depolarization.

B. At rest, excitable cells (e. g. neurons) have a positive charge.

C. Once a depolarization reaches threshold, an action potential will occur and can not be prevented.

D. To reach threshold, cells at rest must hyperpolarize.

E. Repolarization of a neuron results from potassium diffusing out of the cell.

Statements A, C, D and E are correct while statement B is wrong

Explanation:

A. During depolarization phase, the gated sodium ion channels on the neuron's membrane opens for the flow of sodium ions (Na+) into the cell.

C. Once the threshold of depolarization reaches, action potential will occur.

D. Hyperpolarization inhibits action potentials by increasing the stimulus required to move the membrane potential to the action potential threshold.

E. Finally, the cell is brought back to its resting membrane potential by the reflux of extra K + ions out of the cell via the potassium leakage channels.

B is wrong because at rest, excited cells are negatively charged