Question 1

Which of the following best describes the main functional difference between the somatic and autonomic divisions of the peripheral nervous system (PNS)?

Accepted Answer

The somatic division controls voluntary movements of skeletal muscles, while the autonomic division regulates involuntary functions such as heart rate and digestion.

Question 2

A patient is diagnosed with multiple sclerosis, a disease that damages myelin in the CNS. Which type of neuroglial cell is primarily affected?

Accepted Answer

Oligodendrocytes

Question 3

Which of the following best explains why action potentials only travel in one direction along an axon?

Accepted Answer

The absolute refractory period prevents the action potential from traveling backward.

Question 4

A neuron is at rest with a membrane potential of $$-70\ \mathrm{mV}. If $$sodium channels suddenly open, what is the immediate effect on the membrane potential?

Accepted Answer

The membrane potential becomes less negative (depolarization).

Question 5

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

Accepted Answer

Resting state $$\rightarrow$$ Depolarization $$\rightarrow$$ Repolarization $$\rightarrow$$ Hyperpolarization

Question 6

A researcher blocks all voltage-gated potassium channels in a neuron. What is the most likely effect on the action potential?

Accepted Answer

The neuron will not be able to repolarize efficiently, prolonging the action potential.

Question 7

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

Accepted Answer

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

Question 8

A patient is unable to feel pain in their right hand after a nerve injury. Which type of neuron is most likely damaged?

Accepted Answer

Sensory neuron

Question 9

Which of the following statements about graded potentials is correct?

Accepted Answer

Graded potentials decrease in magnitude as they spread from the site of origin.

Question 10

During synaptic transmission at a chemical synapse, which event occurs first?

Accepted Answer

Calcium ions enter the presynaptic terminal.

Question 11

Which neurotransmitter is classified as a biogenic amine and is involved in mood regulation?

Accepted Answer

Serotonin

Question 12

A drug that blocks G protein-linked receptors would most directly affect which type of neurotransmitter action?

Accepted Answer

Slow, indirect modulation of postsynaptic cell activity

Question 13

Which of the following best explains why the absolute refractory period is important for neuronal signaling?

Accepted Answer

It ensures that each action potential is a separate, all-or-none event, preventing overlap.

Question 14

A toxin prevents the reuptake of acetylcholine at the synaptic cleft. What is the most likely effect on synaptic transmission?

Accepted Answer

Postsynaptic cell will be continuously stimulated, leading to prolonged depolarization.

Question 15

Which of the following is a characteristic of inhibitory synapses and IPSPs?

Accepted Answer

They hyperpolarize the postsynaptic membrane, making action potentials less likely.

Question 16

A neuron receives both excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) at the same time. Which of the following best describes the outcome?

Accepted Answer

The net effect depends on the sum of EPSPs and IPSPs at the axon hillock.

Question 17

Which of the following best describes the function of Schwann cells?

Accepted Answer

They form myelin sheaths around axons in the peripheral nervous system.

Question 18

A patient has a genetic mutation that prevents the formation of ependymal cells. Which of the following functions would be most directly affected?

Accepted Answer

Production and circulation of cerebrospinal fluid

Question 19

Which of the following best explains why unmyelinated axons conduct action potentials more slowly than myelinated axons?

Accepted Answer

Unmyelinated axons lack nodes of Ranvier, preventing saltatory conduction.

Question 20

A neuron has a resting membrane potential of $$-70\ \mathrm{mV}. If $$the threshold for firing an action potential is $$-55\ \mathrm{mV}$$, and a graded potential brings the membrane to $$-60\ \mathrm{mV}$$, what will happen?

Accepted Answer

No action potential will be generated because the threshold was not reached.

Neuronal Signaling and the Structure of the Nervous System: Study Guide

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