Resting neuron and the nerve impulse — practice questions

Question 1 · difficulty L1 · recall

Rapid conduction in a myelinated axon by jumping between nodes:

• A. continuous diffusion only
• B. synaptic delay
• C. saltatory conduction
• D. muscle contraction

Question 2 · difficulty L1 · recall

Rapid depolarisation is mainly caused by:

• A. chloride efflux only
• B. sodium influx
• C. potassium influx
• D. calcium precipitation

Question 3 · difficulty L1 · recall

Repolarisation is mainly caused by:

• A. potassium efflux
• B. glucose influx
• C. sodium influx
• D. protein secretion

Question 4 · difficulty L1 · recall

The resting neuronal membrane is normally:

• A. uncharged on both sides
• B. positive inside relative to outside
• C. negative inside relative to outside
• D. permanently depolarised

Question 5 · difficulty L1 · recall

Which ion is normally more concentrated inside a resting neuron than outside?

• A. Calcium
• B. Sodium
• C. Potassium
• D. Chloride

Question 6 · difficulty L2 · understanding

What causes the rapid depolarising phase of a typical neuronal action potential?

• A. Loss of the cell membrane
• B. Opening of potassium channels with potassium influx
• C. Closure of every ion channel
• D. Opening of voltage-gated sodium channels

Question 7 · difficulty L2 · understanding

Which ionic event contributes most to repolarisation after an action potential peak?

• A. Potassium efflux
• B. Sodium influx
• C. Calcium entry into the nucleus
• D. Chloride pumping from the axon

Question 8 · difficulty L3 · application

A stimulus depolarises a neuron but does not reach threshold. What is the likely result?

• A. A larger-than-normal action potential forms
• B. No full action potential is generated
• C. The resting potential is permanently lost
• D. Every terminal releases transmitter

Question 9 · difficulty L4 · analysis

How does the refractory period behind a propagating action potential help nerve conduction?

• A. It permanently blocks the membrane
• B. It triggers a second backward impulse
• C. It limits immediate backward propagation
• D. It releases transmitter from the soma

Question 10 · difficulty L5 · analysis

A neuron loses most of its sodium and potassium gradients after prolonged failure of ATP-dependent ion pumping. What is most likely?

• A. The axon no longer needs ion channels
• B. Conduction becomes faster
• C. The neuron becomes permanently depolarised yet fully normal
• D. Normal resting potential and repeated action potentials become difficult to maintain