Question 1

Which of the following best describes the function of the myelin sheath in neural tissue?

Accepted Answer

It increases the speed of nerve impulse conduction by allowing saltatory propagation.

Question 2

A patient presents with progressive loss of motor control and sensation. MRI reveals demyelination in both the CNS and PNS. Which of the following is most likely impaired?

Accepted Answer

Saltatory conduction of action potentials along axons.

Question 3

Which equation best represents the action of the sodium-potassium pump in maintaining resting membrane potential?

Accepted Answer

For every cycle, $$3\ \mathrm{Na}^+$$ are transported out and $$2\ \mathrm{K}^+$$ are transported in$

Question 4

Which neuroglia cell is primarily responsible for maintaining the blood-brain barrier in the CNS?

Accepted Answer

Astrocytes

Question 5

A neuron receives multiple subthreshold stimuli at different synapses simultaneously. Which process allows these stimuli to combine and potentially trigger an action potential?

Accepted Answer

Spatial summation

Question 6

Which of the following best explains why Type A fibers conduct impulses faster than Type C fibers?

Accepted Answer

Type A fibers are larger in diameter and myelinated, allowing saltatory conduction.

Question 7

Which of the following is TRUE regarding the structural classification of neurons?

Accepted Answer

Multipolar neurons are the most common type in humans and are major in the CNS.

Question 8

Which neurotransmitter is most likely to be involved in regulating motor function and is implicated in Parkinson's disease?

Accepted Answer

Dopamine

Question 9

A nerve fiber is damaged but the cell body remains intact. Which of the following steps is NOT part of the regeneration process in the PNS?

Accepted Answer

Neurolemma remains intact within the endoneurium.

Question 10

Which of the following best describes the effect of an inhibitory neurotransmitter on the postsynaptic membrane?

Accepted Answer

It causes hyperpolarization, increasing membrane potential and suppressing action potential propagation.

Question 11

Which of the following is a direct effect of a neurotransmitter on the postsynaptic cell?

Accepted Answer

Opening gated channels, such as acetylcholine acting on its receptor.

Question 12

Which scenario best illustrates the All-or-None Law of action potentials?

Accepted Answer

A neuron either fires a full action potential or does not fire at all, regardless of stimulus strength above threshold.

Question 13

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

Accepted Answer

Action potentials jump from node to node, a process called saltatory conduction.

Question 14

Which neuroglia cell is most likely to increase in number in response to CNS injury and assist in repair by stabilizing tissue?

Accepted Answer

Astrocytes

Question 15

A patient exposed to tetrodotoxin (TTX) develops paralysis. Which mechanism is most likely disrupted?

Accepted Answer

Normal function of voltage-gated sodium channels, preventing action potential generation.

Question 16

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

Accepted Answer

They migrate through neural tissue and carry out phagocytosis for defense.

Question 17

Which of the following is a characteristic of graded potentials?

Accepted Answer

They decrease in strength over distance and are localized.

Question 18

Which of the following is TRUE regarding the absolute refractory period?

Accepted Answer

The membrane cannot respond to further stimulus, ensuring each action potential is separate.

Question 19

Which scenario best illustrates retrograde axoplasmic transport in neurons?

Accepted Answer

Rabies virus travels from infected tissue toward the cell body, causing cell death.

Question 20

Which of the following best explains the effect of caffeine on neural activity?

Accepted Answer

It lowers the threshold for action potential generation, facilitating neuron firing.

Neural Tissue and Neurophysiology: Structure, Function, and Communication

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