Question 1

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 initiation of another action potential behind the one currently propagating.

Question 2

A patient with multiple sclerosis (MS) is experiencing muscle weakness and slowed reflexes. Which of the following best explains these symptoms?

Accepted Answer

MS leads to demyelination, which slows or blocks saltatory conduction along axons.

Question 3

During the absolute refractory period, which of the following is true about the neuron's ability to fire another action potential?

Accepted Answer

No stimulus, no matter how strong, can trigger another action potential.

Question 4

Which of the following best describes saltatory conduction?

Accepted Answer

Action potentials jump from one node of Ranvier to the next in myelinated axons, increasing conduction speed.

Question 5

A neuron receives two excitatory postsynaptic potentials (EPSPs) in rapid succession at the same synapse. This is an example of:

Accepted Answer

Temporal summation

Question 6

Which of the following equations correctly represents the relationship between conduction velocity ($$v$$), axon diameter ($$d$$), and myelination?

Accepted Answer

$$v = k \cdot \sqrt{d} ($$where $$k is a $$constant, and $$d is $$axon diameter)

Question 7

Which neurotransmitter is most directly associated with neuromuscular junctions and is the first identified and best understood?

Accepted Answer

Acetylcholine

Question 8

A postsynaptic neuron is more likely to fire an action potential if:

Accepted Answer

It receives enough excitatory postsynaptic potentials (EPSPs) to reach threshold.

Question 9

Which of the following best explains how the central nervous system (CNS) codes for stimulus intensity?

Accepted Answer

By increasing the frequency of action potentials received per second.

Question 10

Which of the following is a correct statement about the effect of myelination on axon conduction?

Accepted Answer

Myelination increases conduction velocity by preventing leakage of charge and allowing saltatory conduction.

Question 11

Which of the following neurotransmitters is classified as an amino acid and is the main inhibitory neurotransmitter in the brain?

Accepted Answer

GABA (gamma-aminobutyric acid)

Question 12

A patient is given a drug that blocks voltage-gated sodium channels. What is the most likely effect on neuronal signaling?

Accepted Answer

Action potentials will not be generated, preventing nerve impulse transmission.

Question 13

Which of the following best describes the function of a chemical synapse?

Accepted Answer

It uses neurotransmitters to transmit signals from one neuron to another across a synaptic cleft.

Question 14

Which of the following is true regarding the relative refractory period?

Accepted Answer

A stronger-than-normal stimulus is required to generate another action potential.

Question 15

Which of the following best explains why larger-diameter axons conduct impulses faster than smaller-diameter axons?

Accepted Answer

They have less resistance to local current flow.

Question 16

Which of the following is a correct example of spatial summation?

Accepted Answer

EPSPs from multiple presynaptic neurons arrive at different locations on the postsynaptic neuron at the same time.

Question 17

Which of the following best describes the effect of inhibitory postsynaptic potentials (IPSPs) on a neuron?

Accepted Answer

They hyperpolarize the postsynaptic membrane, making it less likely to fire an action potential.

Question 18

Which of the following is a correct statement about neurotransmitter release at a chemical synapse?

Accepted Answer

Neurotransmitter release is triggered by the influx of calcium ions ($$Ca^{2+}) $$into the presynaptic terminal.

Question 19

Which of the following best explains why action potentials are described as 'all-or-none' events?

Accepted Answer

Once threshold is reached, an action potential of fixed size is generated, regardless of stimulus intensity.

Question 20

Which of the following neurotransmitters is classified as a biogenic amine and is involved in mood regulation?

Accepted Answer

Serotonin

Neural Signaling: Action Potentials, Synaptic Transmission, and Neurotransmitters

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