Q: During an action potential, which event is responsible for the rapid depolarization phase?

Opening of voltage-gated Na\textsuperscript{+} channels

Q: Which equation best represents the Nernst equation for calculating the equilibrium potential of an ion across a membrane?

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

Q: Which of the following best explains why the resting membrane potential of a neuron is typically around -70 mV?

The Na\textsuperscript{+}/K\textsuperscript{+} pump and selective permeability to K\textsuperscript{+} ions maintain a negative charge inside the cell.

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

Opening of K\textsuperscript{+} channels allowing K\textsuperscript{+} to exit the cell

Question 1

Which of the following best describes the role of oligodendrocytes in the nervous system?

Accepted Answer

They form myelin sheaths in the central nervous system (CNS).

Question 2

A patient is experiencing muscle weakness due to impaired signal transmission in their peripheral nervous system. Which neuroglial cell type is most likely affected?

Accepted Answer

Schwann cells

Question 3

During an action potential, which event is responsible for the rapid depolarization phase?

Accepted Answer

Opening of voltage-gated Na	extsuperscript{+} channels

Question 4

Which equation best represents the Nernst equation for calculating the equilibrium potential of an ion across a membrane?

Accepted Answer

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

Question 5

Which neurotransmitter is primarily involved in stimulating muscle contraction at neuromuscular junctions?

Accepted Answer

Acetylcholine

Question 6

A neuron receives both excitatory and inhibitory signals. Which of the following best describes how the neuron decides whether to fire an action potential?

Accepted Answer

The neuron integrates all incoming signals at the axon hillock, and if the membrane potential reaches the threshold, an action potential is initiated.

Question 7

Which of the following best explains why the resting membrane potential of a neuron is typically around -70 mV?

Accepted Answer

The Na	extsuperscript{+}/K	extsuperscript{+} pump and selective permeability to K	extsuperscript{+} ions maintain a negative charge inside the cell.

Question 8

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

Accepted Answer

Opening of K	extsuperscript{+} channels allowing K	extsuperscript{+} to exit the cell

Question 9

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

Accepted Answer

They maintain ion concentrations in the interstitial fluid and communicate with neurons.

Question 10

A patient is given a drug that blocks voltage-gated Na	extsuperscript{+} channels. What effect will this have on neuronal action potentials?

Accepted Answer

Action potentials will not be initiated because depolarization cannot occur.

Question 11

Which of the following is TRUE regarding electrical synapses?

Accepted Answer

Ions flow directly between cells via gap junctions.

Question 12

Which neurotransmitter is most likely to be involved in reducing pain and producing euphoria?

Accepted Answer

Endorphins

Question 13

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

Accepted Answer

They act as immune cells in the CNS.

Question 14

A neuron is exposed to an inhibitory neurotransmitter. What is the most likely effect on the postsynaptic membrane?

Accepted Answer

The membrane potential will become more negative, making it less likely to reach threshold.

Question 15

Which of the following best describes the function of the axon hillock?

Accepted Answer

It is the site where action potentials are initiated if the threshold is reached.

Question 16

Which of the following is a correct sequence of events during an action potential?

Accepted Answer

Depolarization, repolarization, hyperpolarization

Question 17

Which part of the nervous system is responsible for integrating sensory input and coordinating motor output?

Accepted Answer

Central nervous system (CNS)

Question 18

A patient has a genetic mutation that impairs the function of ependymal cells. Which of the following symptoms would most likely result?

Accepted Answer

Reduced production of cerebrospinal fluid

Question 19

Which of the following best explains the effect of excitatory neurotransmitters on the postsynaptic neuron?

Accepted Answer

They decrease the impulse initiation threshold, making an action potential more likely to occur.

Neurons and the Nervous System: Structure, Function, and Communication

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