Question 1

Which of the following best describes the main function of the sensory (afferent) division of the peripheral nervous system (PNS)?

Accepted Answer

It carries sensory information from receptors to the CNS.

Question 2

A patient suffers a spinal cord injury that disrupts the function of Schwann cells. Which of the following is most likely to occur as a result?

Accepted Answer

Loss of myelination in the peripheral nervous system, resulting in impaired nerve signal transmission.

Question 3

Which of the following best explains why the resting membrane potential of a neuron is typically around $$-70\ \mathrm{mV}$$?

Accepted Answer

There are more negatively charged proteins inside the cell and the membrane is more permeable to potassium than sodium.

Question 4

During the generation of an action potential, what event occurs immediately after the membrane potential reaches threshold at the axon hillock?

Accepted Answer

Voltage-gated sodium channels open, causing Na$$^+ to $$rush into the cell.

Question 5

A neuron receives multiple excitatory postsynaptic potentials (EPSPs) at the same synapse in rapid succession. What is this process called, and what is its effect?

Accepted Answer

Temporal summation; it increases the likelihood of an action potential by combining inputs over time at the same synapse.

Question 6

Which of the following statements about graded potentials is correct?

Accepted Answer

They are local changes in membrane potential that can vary in magnitude and may lead to an action potential if threshold is reached.

Question 7

Which of the following best describes the role of the sodium-potassium pump ($$\mathrm{Na^+/K^+}$$ ATPase) in maintaining the resting membrane potential?

Accepted Answer

It pumps three sodium ions out of the cell and two potassium ions into the cell, using ATP.

Question 8

A patient is diagnosed with a disease that destroys oligodendrocytes. Which of the following symptoms would most likely be observed?

Accepted Answer

Impaired myelination in the CNS, leading to slower nerve conduction and possible muscle weakness.

Question 9

Which of the following is a characteristic of type A nerve fibers?

Accepted Answer

They are myelinated, have a large diameter, and conduct impulses rapidly.

Question 10

Which of the following best explains the difference between a chemical synapse and an electrical synapse?

Accepted Answer

Chemical synapses use neurotransmitters to transmit signals across a synaptic cleft, while electrical synapses transmit signals via direct ion flow through gap junctions.

Question 11

A neuron is exposed to a drug that blocks voltage-gated potassium channels. What effect will this have on the action potential?

Accepted Answer

It will prolong repolarization, causing the action potential to last longer.

Question 12

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

Accepted Answer

They perform phagocytic duties, removing debris and pathogens.

Question 13

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

Accepted Answer

No action potential can be generated, regardless of stimulus strength.

Question 14

Which of the following best explains why saltatory conduction is faster than continuous conduction?

Accepted Answer

Saltatory conduction allows the action potential to jump from one node of Ranvier to the next, reducing the number of times the membrane must depolarize.

Question 15

A patient has a mutation that causes all of their sodium leak channels to be nonfunctional. What is the most likely effect on their neurons' resting membrane potential?

Accepted Answer

The resting membrane potential would become more negative because less sodium would enter the cell.

Question 16

Which of the following is a function of astrocytes in the central nervous system?

Accepted Answer

They maintain the blood-brain barrier and regulate the extracellular environment.

Question 17

Which of the following best describes the process of Wallerian degeneration?

Accepted Answer

It is the degeneration of the axon distal to the site of injury in the PNS.

Question 18

Which of the following neurotransmitters is classified as a biogenic amine and is primarily involved in the 'fight or flight' response?

Accepted Answer

Norepinephrine

Question 19

A neuron receives both excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) at the same time. What determines whether the neuron will fire an action potential?

Accepted Answer

The net effect of all EPSPs and IPSPs at the axon hillock.

Question 20

Which of the following best describes the function of the autonomic nervous system?

Accepted Answer

It regulates involuntary functions such as heart rate, digestion, and respiratory rate.

Study Guide: Nervous System Structure and Function (Chapter 12.1–12.8)

Study Guide - Practice Questions

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