Question 1

Which of the following best describes the role of the sodium-potassium pump in maintaining the resting membrane potential (RMP) of a neuron?

Accepted Answer

It pumps 3 Na+ ions out of the cell and 2 K+ ions into the cell using ATP, maintaining a negative charge inside.

Question 2

During the depolarization phase of an action potential, which of the following occurs?

Accepted Answer

Voltage-gated Na+ channels open, allowing Na+ to enter the cell.

Question 3

What is the primary reason the inside of a neuron is more negative than the outside at rest?

Accepted Answer

There are more negatively charged anions (proteins, phosphates) inside the cell.

Question 4

Which equation can be used to calculate the equilibrium potential for a single ion, such as K+?

Accepted Answer

$$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{outside}}{[ion]_{inside}} \right)$$

Question 5

A patient with multiple sclerosis (MS) is likely to experience which of the following due to the loss of myelin in the CNS?

Accepted Answer

Slower nerve signal transmission and muscle weakness

Question 6

Which of the following best explains why action potentials only travel in one direction along an axon?

Accepted Answer

The refractory period prevents the area behind the action potential from being re-excited immediately.

Question 7

Which of the following is true regarding saltatory conduction in myelinated axons?

Accepted Answer

Action potentials jump from one node of Ranvier to the next, increasing conduction speed.

Question 8

During the repolarization phase of an action potential, which of the following occurs?

Accepted Answer

Voltage-gated K+ channels open and K+ exits the cell.

Question 9

A neuron is exposed to a toxin that blocks voltage-gated Na+ channels. What is the most likely effect on nerve signaling?

Accepted Answer

The neuron will be unable to generate or propagate action potentials.

Question 10

Which of the following best describes the difference between ligand-gated and voltage-gated ion channels?

Accepted Answer

Ligand-gated channels open in response to neurotransmitter binding, while voltage-gated channels open in response to changes in membrane voltage.

Question 11

Which of the following is a direct consequence of the hyperpolarization phase in an action potential?

Accepted Answer

The membrane potential becomes more negative than at rest due to continued K+ efflux.

Question 12

A patient is diagnosed with Parkinson’s disease. Which neurotransmitter is most directly involved in the pathophysiology of this disorder?

Accepted Answer

Dopamine

Question 13

Which of the following best explains why the sodium-potassium pump requires ATP to function?

Accepted Answer

It moves Na+ and K+ ions against their concentration gradients.

Question 14

Which of the following scenarios would most likely result in a neuron failing to return to its resting membrane potential after an action potential?

Accepted Answer

The sodium-potassium pump is inhibited and cannot function.

Question 15

Which of the following best describes the process of neurotransmitter removal from the synaptic cleft?

Accepted Answer

Neurotransmitters are broken down by enzymes or reabsorbed by the presynaptic neuron.

Question 16

Which of the following is a characteristic of continuous conduction in unmyelinated axons?

Accepted Answer

Action potentials are generated at every point along the axon.

Question 17

A neuron is exposed to a drug that increases the permeability of the membrane to K+ ions at rest. What is the most likely effect on the resting membrane potential?

Accepted Answer

The resting membrane potential will become more negative (hyperpolarized).

Question 18

Which of the following best explains why myelinated axons conduct action potentials more rapidly than unmyelinated axons?

Accepted Answer

Myelin sheaths allow action potentials to jump from node to node, reducing the number of action potentials needed.

Nerve Signaling and Membrane Potentials in the Nervous System

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