Question 1

Which type of axonal conduction is characterized by the unidirectional spread of an action potential along the entire length of the plasma membrane, typically in unmyelinated axons?

Accepted Answer

Continuous conduction

Question 2

During saltatory conduction, where are action potentials generated?

Accepted Answer

Only at the nodes of Ranvier

Question 3

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

Accepted Answer

Saltatory conduction allows action potentials to jump between myelinated segments, reducing the number of depolarizations required.

Question 4

A new drug blocks sodium channels in the axons of a neuron. What effect would this have?

Accepted Answer

It would prevent the propagation of action potentials.

Question 5

In unmyelinated axons, action potentials are propagated by which type of conduction?

Accepted Answer

Continuous conduction

Question 6

If the myelin sheath is damaged, what is the most likely effect on the speed of action potential propagation?

Accepted Answer

It will decrease because saltatory conduction is impaired.

Question 7

Which of the following equations best represents the relationship between conduction velocity ($$v) $$and axon diameter ($$d) in $$myelinated axons?

Accepted Answer

$$v = k 	imes d$$

Question 8

A patient with multiple sclerosis experiences slowed nerve conduction. Which physiological change is most directly responsible for this symptom?

Accepted Answer

Destruction of myelin sheaths, impairing saltatory conduction

Question 9

Which statement about the propagation of action potentials is correct?

Accepted Answer

Saltatory conduction involves action potentials jumping from node to node.

Question 10

If a neuron’s axon is completely unmyelinated, which of the following is true regarding the propagation of action potentials?

Accepted Answer

Action potentials propagate slowly along the entire axon membrane.

Question 11

Which of the following would most likely increase the speed of action potential propagation in an axon?

Accepted Answer

Increasing the thickness of the myelin sheath

Question 12

A researcher measures the time it takes for an action potential to travel down a myelinated axon and finds it is much faster than in an unmyelinated axon of the same diameter. What is the best explanation for this observation?

Accepted Answer

Saltatory conduction allows action potentials to skip myelinated regions, increasing speed.

Question 13

Which of the following is a direct consequence of blocking sodium channels in the axon membrane?

Accepted Answer

Inhibition of action potential propagation

Question 14

Which of the following best describes the role of the nodes of Ranvier in saltatory conduction?

Accepted Answer

They are the only sites where action potentials are regenerated.

Question 15

If the axon diameter is doubled, how does this affect the conduction velocity in a myelinated axon, assuming $$v = k 	imes d$$?

Accepted Answer

Conduction velocity is doubled.

Question 16

Which of the following is NOT a feature of continuous conduction?

Accepted Answer

Action potentials jump from node to node

Question 17

A patient is given a drug that selectively blocks potassium channels in the axon. What is the most likely effect on action potential propagation?

Accepted Answer

Action potentials will propagate, but repolarization will be delayed.

Question 18

Which of the following best describes the difference between graded potentials and action potentials?

Accepted Answer

Graded potentials can summate, while action potentials cannot.

Question 19

Which of the following is true regarding the propagation of action potentials in myelinated axons?

Accepted Answer

Action potentials are generated only at the nodes of Ranvier.

Question 20

A neuron is exposed to a toxin that destroys its myelin sheath. Which of the following is the most likely outcome?

Accepted Answer

Saltatory conduction will be impaired, leading to slower action potential propagation.

Propagation of Action Potentials in Neurons: Continuous vs. Saltatory Conduction

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