Question 1

Which of the following best explains why action potentials travel faster in myelinated axons compared to unmyelinated axons?

Accepted Answer

Myelin increases membrane resistance and enables saltatory conduction between nodes of Ranvier.

Question 2

A patient presents with hyperkalemia. Which of the following best describes the effect of this condition on neuronal excitability?

Accepted Answer

The neuron becomes more likely to fire an action potential because the membrane potential is closer to threshold.

Question 3

Which of the following equations correctly represents Ohm's Law as it applies to the movement of ions across a neuronal membrane?

Accepted Answer

$$V = I 	imes R$$

Question 4

Which neurotransmitter is synthesized from choline and acetyl CoA, and acts on both nicotinic and muscarinic receptors?

Accepted Answer

Acetylcholine

Question 5

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

Accepted Answer

Spatial summation

Question 6

Which of the following is a characteristic of electrical synapses?

Accepted Answer

They allow bi-directional flow of electrical signals through gap junctions.

Question 7

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

Accepted Answer

It acts as an inhibitory neurotransmitter by opening Cl- channels, hyperpolarizing the target cell.

Question 8

During the absolute refractory period of an action potential, which of the following is true?

Accepted Answer

No stimulus, regardless of strength, can initiate another action potential.

Question 9

Which of the following best describes the process of neurotransmitter release at a chemical synapse?

Accepted Answer

An action potential opens voltage-gated Ca2+ channels, leading to exocytosis of neurotransmitter vesicles.

Question 10

Which of the following is a correct example of synaptic plasticity?

Accepted Answer

A change in the number or strength of synaptic connections in response to activity.

Question 11

Which of the following best describes the difference between nicotinic and muscarinic acetylcholine receptors?

Accepted Answer

Nicotinic receptors are ion channels, while muscarinic receptors are G protein-coupled.

Question 12

A patient is given a drug that inhibits acetylcholinesterase. What is the most likely effect at cholinergic synapses?

Accepted Answer

Increased acetylcholine in the synaptic cleft and prolonged postsynaptic response.

Question 13

Which of the following best describes the process of long-term potentiation (LTP) in the central nervous system?

Accepted Answer

A sustained increase in synaptic strength, often involving glutamate and NMDA/AMPA receptors.

Question 14

Which of the following scenarios best illustrates presynaptic inhibition?

Accepted Answer

A modulatory neuron decreases neurotransmitter release from a presynaptic terminal, reducing the postsynaptic response.

Question 15

Which of the following neurotransmitters is derived from tyrosine and is involved in both the central and peripheral nervous systems?

Accepted Answer

Norepinephrine

Question 16

A neuron receives multiple subthreshold EPSPs in rapid succession from the same presynaptic neuron. What is this process called?

Accepted Answer

Temporal summation

Question 17

Which of the following best describes the effect of hypokalemia on neuronal excitability?

Accepted Answer

It moves the membrane potential further from threshold, decreasing excitability.

Question 18

Which of the following is true regarding the difference between fast and slow postsynaptic potentials?

Accepted Answer

Fast postsynaptic potentials involve direct opening of ion channels, while slow potentials involve G protein-coupled receptors.

Question 19

Which of the following best describes the concept of convergence in neural pathways?

Accepted Answer

Multiple presynaptic neurons provide input to a single postsynaptic neuron.

Question 20

Which of the following is a correct statement about the termination of neurotransmitter activity at a synapse?

Accepted Answer

Neurotransmitter activity can be terminated by enzymatic breakdown, diffusion, or reuptake into cells.

Neural Communication: Action Potentials, Synapses, and Integration

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