Multiple Choice
In the context of neurons and action potentials, what change in a neuron is typically measured on the y-axis of an action potential graph?
22
views
45. Nervous System
Neurons and Action Potentials
Struggling with General Biology?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Which of the following types of neurons is likely to propagate an action potential the fastest?
A
A large-diameter, myelinated axon
B
A small-diameter, myelinated axon
C
A large-diameter, unmyelinated axon
D
A small-diameter, unmyelinated axon
Verified step by step guidance1
Understand the factors that influence the speed of action potential propagation: The two main factors are the diameter of the axon and whether or not the axon is myelinated. Larger diameters reduce resistance to ion flow, and myelination allows for saltatory conduction, both of which increase speed.
Recall the role of myelination: Myelin sheaths insulate the axon and allow the action potential to 'jump' between nodes of Ranvier (gaps in the myelin sheath). This process, called saltatory conduction, significantly increases the speed of signal transmission compared to unmyelinated axons.
Consider the effect of axon diameter: Larger-diameter axons have less internal resistance to the flow of ions, which allows the action potential to propagate more quickly compared to smaller-diameter axons.
Compare the options: A large-diameter, myelinated axon combines both factors (large diameter and myelination) that maximize the speed of action potential propagation. The other options lack one or both of these factors, making them slower in comparison.
Conclude that the fastest propagation of an action potential will occur in a large-diameter, myelinated axon, as it benefits from both reduced resistance and saltatory conduction.
Related Videos
Related Practice
Neurons and Action Potentials practice set
Problem sets built by lead tutorsExpert video explanations