Q: Which of the following best describes the role of the sodium-potassium pump in maintaining the resting membrane potential of a neuron?

It actively transports 3 Na\textsuperscript{+} ions out of the cell and 2 K\textsuperscript{+} ions into the cell per ATP hydrolyzed.

Q: A neuron at rest has a membrane potential of approximately $-70\ \mathrm{mV}$. Which of the following factors contributes MOST to this negative resting potential?

The movement of K\textsuperscript{+} ions out of the cell through leak channels.

Q: During the generation of an action potential, which event occurs immediately after the membrane potential reaches threshold ($\approx -55\ \mathrm{mV}$)?

Voltage-gated Na\textsuperscript{+} channels open rapidly, causing Na\textsuperscript{+} influx.

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

The trapping of large anions (A\textsuperscript{-}) such as proteins inside the cell.

Q: In a mammalian neuron, which of the following correctly describes the relative concentrations of K\textsuperscript{+} and Na\textsuperscript{+} ions inside and outside the cell at rest?

K\textsuperscript{+} is higher inside; Na\textsuperscript{+} is higher outside.

Question 1

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

Accepted Answer

It actively transports 3 Na	extsuperscript{+} ions out of the cell and 2 K	extsuperscript{+} ions into the cell per ATP hydrolyzed.

Question 2

A neuron at rest has a membrane potential of approximately $-70\ \mathrm{mV}$. Which of the following factors contributes MOST to this negative resting potential?

Accepted Answer

The movement of K	extsuperscript{+} ions out of the cell through leak channels.

Question 3

During the generation of an action potential, which event occurs immediately after the membrane potential reaches threshold ($\approx -55\ \mathrm{mV}$)?

Accepted Answer

Voltage-gated Na	extsuperscript{+} channels open rapidly, causing Na	extsuperscript{+} influx.

Question 4

Which type of glial cell is responsible for forming the myelin sheath in the peripheral nervous system?

Accepted Answer

Schwann cell

Question 5

A patient is exposed to a neurotoxin that blocks voltage-gated sodium channels. What is the most likely effect on neuronal signaling?

Accepted Answer

Action potentials will not be initiated.

Question 6

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

Accepted Answer

The trapping of large anions (A	extsuperscript{-}) such as proteins inside the cell.

Question 7

Which of the following is TRUE regarding the 'all-or-none' nature of action potentials?

Accepted Answer

Action potentials only occur if the membrane depolarization reaches threshold.

Question 8

Which ion channel is primarily responsible for restoring the membrane potential after an action potential?

Accepted Answer

Voltage-gated potassium channel

Question 9

In a mammalian neuron, which of the following correctly describes the relative concentrations of K	extsuperscript{+} and Na	extsuperscript{+} ions inside and outside the cell at rest?

Accepted Answer

K	extsuperscript{+} is higher inside; Na	extsuperscript{+} is higher outside.

Question 10

Which of the following best describes the sequence of information processing in the nervous system?

Accepted Answer

Sensory input → Integration → Motor output

Question 11

A mutation causes voltage-gated potassium channels to open more slowly than normal. What is the most likely effect on the action potential?

Accepted Answer

The depolarization phase will be prolonged.

Question 12

Which of the following is a function of astrocytes in the central nervous system?

Accepted Answer

Supporting neurons and forming the blood-brain barrier

Question 13

Which of the following best describes the role of voltage-gated calcium channels at the synaptic terminal?

Accepted Answer

They allow Ca	extsuperscript{2+} influx, triggering neurotransmitter release.

Question 14

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

Accepted Answer

Opening of voltage-gated K	extsuperscript{+} channels

Question 15

Which of the following is TRUE about interneurons?

Accepted Answer

They process information between sensory and motor neurons.

Question 16

A researcher records the frequency of action potentials in a sensory neuron in response to increasing pressure on the skin. What is the most likely observation?

Accepted Answer

The frequency of action potentials increases with pressure.

Question 17

Which of the following best describes the function of microglia in the central nervous system?

Accepted Answer

They protect the nervous system from microorganisms.

Question 18

Which of the following statements about synapses is CORRECT?

Accepted Answer

The synaptic terminal releases neurotransmitters into the synaptic cleft.

Question 19

Which equation best represents the Nernst equation for calculating the equilibrium potential ($E_{ion}$) of an ion across a membrane?

Accepted Answer

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

The Nervous System I: Neuron Structure, Function, and Action Potentials

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