Q: A patient is given a local anesthetic such as lidocaine before a minor surgical procedure. Which mechanism best explains how this drug prevents pain sensation?

It prevents the opening of voltage-gated Na\textsuperscript{+} channels, stopping action potential propagation.

Q: Which equation correctly 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: During the depolarizing phase of an action potential, which ion channels open and what is the direction of ion movement?

Voltage-gated Na\textsuperscript{+} channels open; Na\textsuperscript{+} moves into the cell.

Question 1

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

Accepted Answer

They regulate the composition of the interstitial fluid and help maintain the blood-brain barrier.

Question 2

A patient is given a local anesthetic such as lidocaine before a minor surgical procedure. Which mechanism best explains how this drug prevents pain sensation?

Accepted Answer

It prevents the opening of voltage-gated Na	extsuperscript{+} channels, stopping action potential propagation.

Question 3

Which equation correctly 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 4

Which of the following statements about graded potentials is TRUE?

Accepted Answer

Graded potentials can summate to trigger an action potential if threshold is reached.

Question 5

A neuron receives simultaneous excitatory inputs from multiple presynaptic neurons. What is this process called?

Accepted Answer

Spatial summation

Question 6

Which glial cell type is responsible for myelinating axons in the peripheral nervous system (PNS)?

Accepted Answer

Schwann cells

Question 7

During the depolarizing phase of an action potential, which ion channels open and what is the direction of ion movement?

Accepted Answer

Voltage-gated Na	extsuperscript{+} channels open; Na	extsuperscript{+} moves into the cell.

Question 8

Which of the following best explains why myelinated axons conduct impulses faster than unmyelinated axons?

Accepted Answer

Myelinated axons allow action potentials to jump from node to node via saltatory conduction.

Question 9

Which neurotransmitter is released by motor neurons at the neuromuscular junction to stimulate muscle contraction?

Accepted Answer

Acetylcholine (ACh)

Question 10

A patient with multiple sclerosis (MS) is experiencing muscle weakness and abnormal sensations. What is the underlying cause of these symptoms?

Accepted Answer

Autoimmune destruction of myelin sheaths in the CNS

Question 11

Which of the following is a function of the enteric nervous system (ENS)?

Accepted Answer

Monitoring chemical changes within the GI tract and controlling GI motility

Question 12

Which of the following best describes the role of microglia in the CNS?

Accepted Answer

They act as phagocytes, clearing away dead cells and debris.

Question 13

Which of the following statements about action potentials is CORRECT?

Accepted Answer

Action potentials are all-or-none events and do not vary in amplitude.

Question 14

Which process is responsible for the removal of neurotransmitter from the synaptic cleft by enzymatic breakdown?

Accepted Answer

Enzymatic degradation

Question 15

Which of the following is TRUE regarding the refractory period of an action potential?

Accepted Answer

It ensures that action potentials only travel in one direction along the axon.

Question 16

Which of the following best describes the difference between graded potentials and action potentials?

Accepted Answer

Graded potentials vary in amplitude depending on stimulus strength, while action potentials are all-or-none.

Question 17

Which of the following is a biogenic amine neurotransmitter involved in mood, dreaming, and emotional responses?

Accepted Answer

Serotonin

Question 18

Which structural classification of neuron is most commonly found in sensory neurons of the PNS?

Accepted Answer

Unipolar neuron

Question 19

A patient is exposed to strychnine, a poison that blocks glycine receptors in the spinal cord. What is the most likely effect?

Accepted Answer

Massive, sustained contractions of skeletal muscles

Nervous Tissue: Structure, Function, and Clinical Correlates

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