Question 1

Which of the following best describes the role of Schwann cells in the peripheral nervous system (PNS)?

Accepted Answer

They form the myelin sheath around axons, aiding in the repair and regeneration of damaged neurons.

Question 2

A patient suffers a spinal cord injury that damages the axons of motor neurons. Which process is most likely to occur in the PNS but not in the CNS?

Accepted Answer

Wallerian degeneration followed by axonal regeneration due to Schwann cell activity.

Question 3

Which neurotransmitter is primarily associated with the parasympathetic division of the autonomic nervous system and somatic motor neurons?

Accepted Answer

Acetylcholine (ACh)

Question 4

Which of the following statements about graded potentials is TRUE?

Accepted Answer

The effect of a graded potential decreases with distance from the site of stimulation.

Question 5

During an action potential, what is the primary event that occurs at +30 mV?

Accepted Answer

Inactivation gates of voltage-gated Na$$^+$$ channels close and voltage-gated K$$^+$$ channels open.

Question 6

Which equation best represents the Nernst equation for calculating the equilibrium potential for potassium ions ($$K^+) $$across a neuronal membrane?

Accepted Answer

$$E_{K^+} = \frac{RT}{zF} \ln \left( \frac{[K^+]_{out}}{[K^+]_{in}} \right)$$

Question 7

A neuron receives multiple excitatory postsynaptic potentials (EPSPs) from different presynaptic neurons at the same time. What is this process called?

Accepted Answer

Spatial summation

Question 8

Which type of neuroglial cell is responsible for forming the blood-brain barrier in the CNS?

Accepted Answer

Astrocytes

Question 9

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

Accepted Answer

Type A fibers are myelinated and have a larger diameter, reducing resistance to ion flow.

Question 10

Which of the following is a function of neuromodulators such as opioids in the nervous system?

Accepted Answer

They can increase or decrease the action of neurotransmitters at a synapse by acting on G-protein coupled receptors.

Question 11

Which of the following best describes the absolute refractory period during an action potential?

Accepted Answer

A period when no additional action potential can be generated, regardless of stimulus strength.

Question 12

Which of the following is TRUE regarding the resting membrane potential of a neuron?

Accepted Answer

It is primarily established by the differential distribution of Na$$^+$$ and K$$^+$$ ions across the membrane and the activity of the Na$$^+/K$^+$$ ATPase pump.

Question 13

A neuron is exposed to a drug that blocks voltage-gated sodium channels. What is the most likely effect on the neuron's ability to generate an action potential?

Accepted Answer

The neuron will be unable to depolarize and generate an action potential.

Question 14

Which of the following best describes the function of the axon hillock in a neuron?

Accepted Answer

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

Question 15

Which structural type of neuron is most commonly found in the central nervous system and includes all skeletal muscle motor neurons?

Accepted Answer

Multipolar neuron

Question 16

Which of the following scenarios best illustrates temporal summation?

Accepted Answer

A single presynaptic neuron releases neurotransmitter repeatedly in rapid succession, causing multiple EPSPs in the postsynaptic neuron.

Question 17

Which of the following is a key difference between the central nervous system (CNS) and the peripheral nervous system (PNS) in terms of neuron repair?

Accepted Answer

The PNS has Schwann cells that promote axonal regeneration, while the CNS lacks this efficient repair mechanism.

Question 18

Which neurotransmitter is most closely associated with learning and memory in the brain?

Accepted Answer

Glutamate

Question 19

A neuron receives both excitatory and inhibitory inputs. What determines whether it will fire an action potential?

Accepted Answer

The sum of all EPSPs and IPSPs at the axon hillock must reach threshold.

Ch 12: The Nervous System: Structure, Function, and Neural Activity

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