Q: During the rising phase of the action potential, which ion movement is primarily responsible for the rapid depolarization of the neuron?

Influx of Na\textsuperscript{+} ions

Q: Which of the following scenarios would most likely result in a hyperpolarization of the postsynaptic membrane?

Opening of ligand-gated K\textsuperscript{+} channels

Question 1

Which of the following correctly matches a glial cell with its primary function in the nervous system?

Accepted Answer

Astrocyte: regulates the extracellular environment and supports the blood-brain barrier

Question 2

A patient suffers a spinal cord injury that damages oligodendrocytes but not Schwann cells. Which of the following is most likely to occur?

Accepted Answer

Myelination in the central nervous system is lost, but peripheral nervous system myelination remains intact.

Question 3

Which of the following best describes the direction of information flow in a typical neuron?

Accepted Answer

Dendrite → soma → axon → axon terminals

Question 4

If the sodium-potassium pump in a neuron is inhibited, what is the most likely immediate effect on the resting membrane potential?

Accepted Answer

The resting membrane potential becomes less negative (depolarized).

Question 5

Which of the following changes would most likely increase the speed of action potential propagation along an axon?

Accepted Answer

Increasing myelination of the axon

Question 6

A drug blocks the reuptake of neurotransmitters from the synaptic cleft. What is the most likely effect on synaptic signaling?

Accepted Answer

Signaling is increased because neurotransmitters remain longer in the synaptic cleft.

Question 7

During the rising phase of the action potential, which ion movement is primarily responsible for the rapid depolarization of the neuron?

Accepted Answer

Influx of Na	extsuperscript{+} ions

Question 8

Which of the following best explains why action potentials travel faster in myelinated axons compared to unmyelinated axons?

Accepted Answer

Myelin allows for saltatory conduction, where the action potential jumps between nodes of Ranvier.

Question 9

A neuron is experimentally depolarized to a membrane potential just below threshold. What is the most likely outcome?

Accepted Answer

No action potential is generated.

Question 10

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

Accepted Answer

Opening of ligand-gated K	extsuperscript{+} channels

Question 11

Which cell type is responsible for myelinating axons in the peripheral nervous system?

Accepted Answer

Schwann cell

Question 12

If voltage-gated Ca	extsuperscript{2+} channels in the presynaptic terminal are blocked, what is the most immediate effect on synaptic transmission?

Accepted Answer

Neurotransmitter release is inhibited.

Question 13

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

Accepted Answer

Providing immune defense and clearing debris

Question 14

Which of the following is a key difference between the central and peripheral nervous systems regarding regeneration after injury?

Accepted Answer

Peripheral nervous system neurons have a greater capacity for regeneration due to the presence of Schwann cells.

Question 15

A mutation causes voltage-gated K	extsuperscript{+} channels to open more slowly during an action potential. What is the most likely effect on the action potential waveform?

Accepted Answer

The falling phase is prolonged, and repolarization is slower.

Question 16

Which of the following best describes saltatory conduction?

Accepted Answer

Action potential jumping from one node of Ranvier to the next in myelinated axons

Question 17

Which of the following would most likely decrease the amount of signaling between a presynaptic neuron and its target cell?

Accepted Answer

Increasing the rate of neurotransmitter clearance from the synaptic cleft

Question 18

Which of the following is NOT a typical function of astrocytes?

Accepted Answer

Forming myelin sheaths around axons

Question 19

A toxin causes the postsynaptic membrane to remain depolarized for an extended period after neurotransmitter binding. Which of the following is a likely consequence?

Accepted Answer

The postsynaptic neuron is more likely to fire repeated action potentials.

Question 20

Which of the following best describes the 'undershoot' phase of the action potential?

Accepted Answer

The membrane potential temporarily becomes more negative than the resting potential due to continued K	extsuperscript{+} efflux.

Neurons and Glial Cells: Structure, Function, and Signaling

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