Question 1

Which of the following best describes the resting membrane potential of a typical neuron?

Accepted Answer

The inside of the neuron is negative relative to the outside, with a difference of approximately $$-70\ \mathrm{mV}.$$

Question 2

Which ions are most concentrated inside and outside a neuron at rest, respectively?

Accepted Answer

Potassium ($$\mathrm{K}^+) $$inside, Sodium ($$\mathrm{Na}^+) $$outside

Question 3

What is the primary function of the sodium-potassium pump in maintaining the resting membrane potential?

Accepted Answer

It moves $$3\ \mathrm{Na}^+$$ ions out of the cell for every $$2\ \mathrm{K}^+$$ ions in.

Question 4

Which of the following best explains why neurons require a constant supply of energy, even when a person is asleep?

Accepted Answer

To maintain the sodium-potassium pump, which preserves ionic gradients across the membrane.

Question 5

A drug that blocks voltage-gated sodium channels would have which of the following effects on neuronal communication?

Accepted Answer

It would prevent the initiation and propagation of action potentials.

Question 6

Which process is responsible for moving ions down their concentration gradient across the neuronal membrane?

Accepted Answer

Diffusion

Question 7

During the action potential, which event occurs immediately after the threshold is reached?

Accepted Answer

Voltage-gated sodium channels open, allowing $$\mathrm{Na}^+ to $$enter the cell.

Question 8

Which of the following best describes the 'all-or-none' principle of the action potential?

Accepted Answer

Once threshold is reached, an action potential of fixed size and duration is generated.

Question 9

What is the main reason action potentials travel faster in myelinated axons compared to unmyelinated axons?

Accepted Answer

Myelin allows for saltatory conduction, where the action potential jumps between nodes of Ranvier.

Question 10

Which of the following is NOT a function of the refractory period in neurons?

Accepted Answer

Allows for the summation of postsynaptic potentials.

Question 11

A patient is given a drug that blocks acetylcholinesterase. What is the most likely effect on synaptic transmission at the neuromuscular junction?

Accepted Answer

Acetylcholine will remain in the synaptic cleft longer, enhancing muscle contraction.

Question 12

Which of the following best describes the difference between ionotropic and metabotropic receptors?

Accepted Answer

Ionotropic receptors are ligand-gated ion channels that produce rapid, short-lived effects; metabotropic receptors act through second messengers and produce slower, longer-lasting effects.

Question 13

Which of the following is a correct sequence in the 'life cycle' of a neurotransmitter?

Accepted Answer

Synthesis → Storage in vesicles → Release → Binding to postsynaptic receptors → Deactivation

Question 14

A new drug acts as an antagonist at dopamine receptors. Which of the following effects is most likely?

Accepted Answer

It blocks dopamine receptors, reducing dopamine's effects.

Question 15

Which neurotransmitter is most closely associated with fast, excitatory synaptic transmission in the central nervous system?

Accepted Answer

Glutamate

Question 16

Which of the following best explains how benzodiazepines act as GABA agonists?

Accepted Answer

They bind to the GABA receptor and increase the binding of GABA, enhancing inhibitory effects.

Question 17

A patient with epilepsy is prescribed a drug that increases GABA activity in the brain. What is the most likely effect of this drug?

Accepted Answer

It will decrease neuronal excitability, reducing the likelihood of seizures.

Question 18

Which of the following is a real-world example of an agonist drug effect?

Accepted Answer

Cocaine blocking dopamine reuptake, increasing dopamine activity.

Question 19

If a neuron receives multiple excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) at the same time, 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 (approximately $$-65\ \mathrm{mV}).$$

Question 20

Which of the following mechanisms is NOT a way to deactivate neurotransmitters in the synaptic cleft?

Accepted Answer

Continuous stimulation of the postsynaptic receptor

Neural Conduction and Synaptic Transmission: Resting Membrane Potential and Ionic Mechanisms

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