Q: What is the primary function of the Na\textsuperscript{+}/K\textsuperscript{+} ATPase pump in establishing the resting membrane potential?

It pumps Na\textsuperscript{+} out of the cell and K\textsuperscript{+} into the cell, maintaining their concentration gradients.

Q: Which of the following best explains why the inside of a neuron is negatively charged at rest?

The Na\textsuperscript{+}/K\textsuperscript{+} pump moves more positive charges out than in.

Question 1

Which type of ion channel opens in response to the binding of a neurotransmitter to its receptor on the channel?

Accepted Answer

Ligand-gated channel

Question 2

What is the primary function of the Na	extsuperscript{+}/K	extsuperscript{+} ATPase pump in establishing the resting membrane potential?

Accepted Answer

It pumps Na	extsuperscript{+} out of the cell and K	extsuperscript{+} into the cell, maintaining their concentration gradients.

Question 3

A neuron is at rest with a membrane potential of $$V_m = -70\ \mathrm{mV}. If $$ligand-gated Na	extsuperscript{+} channels open, what is the expected effect on $$V_m$$?

Accepted Answer

$$V_m$$ will become less negative (depolarization).

Question 4

Which equation is used to calculate the equilibrium potential for a specific ion across a membrane?

Accepted Answer

The Nernst equation: $$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$$

Question 5

During the absolute refractory period of an action potential, which of the following is true?

Accepted Answer

No stimulus, regardless of strength, can trigger another action potential.

Question 6

Saltatory conduction is faster than continuous conduction because:

Accepted Answer

Action potentials jump from one node of Ranvier to the next, skipping myelinated regions.

Question 7

Which of the following best describes graded potentials?

Accepted Answer

They vary in size and can be either depolarizing or hyperpolarizing.

Question 8

If the extracellular concentration of K	extsuperscript{+} increases, what happens to the resting membrane potential ($$V_m) of a $$neuron?

Accepted Answer

$$V_m$$ becomes less negative (depolarizes).

Question 9

Which of the following is a characteristic of action potentials but NOT graded potentials?

Accepted Answer

They are all-or-nothing and propagate in one direction.

Question 10

A patient presents with a mutation that causes voltage-gated Na	extsuperscript{+} channels to remain open longer than normal. What is the most likely effect on the action potential?

Accepted Answer

Prolonged depolarization phase and delayed repolarization.

Question 11

Which of the following best explains why the inside of a neuron is negatively charged at rest?

Accepted Answer

The Na	extsuperscript{+}/K	extsuperscript{+} pump moves more positive charges out than in.

Question 12

Which of the following scenarios would most likely result in hyperpolarization of a neuron?

Accepted Answer

Opening of ligand-gated Cl	extsuperscript{–} channels.

Question 13

Which of the following is TRUE regarding the propagation of action potentials in myelinated axons?

Accepted Answer

Action potentials travel faster due to saltatory conduction.

Question 14

A neuron receives two simultaneous stimuli: one causes depolarization and the other causes hyperpolarization. What is the resulting membrane potential change called?

Accepted Answer

Spatial summation

Question 15

Which of the following best describes the role of voltage-gated K	extsuperscript{+} channels during an action potential?

Accepted Answer

They open during repolarization to allow K	extsuperscript{+} efflux.

Question 16

Which of the following is NOT a stimulus for opening a mechanically gated ion channel?

Accepted Answer

Binding of a ligand

Question 17

If a neuron is exposed to a toxin that blocks all K	extsuperscript{+} leak channels, what is the most likely effect on the resting membrane potential?

Accepted Answer

The resting membrane potential will become less negative.

Question 18

Which of the following is a property of continuous conduction in neurons?

Accepted Answer

It occurs in unmyelinated axons.

Question 19

A neuron is stimulated so that its membrane potential changes from $$-70\ \mathrm{mV} to$$ $$-55\ \mathrm{mV}. $$What is this point called?

Accepted Answer

Threshold potential

Electrophysiology of Neurons: Ion Channels, Electrochemical Gradients, and Membrane Potentials

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