The Nodes of Ranvier are the small gaps in the myelin sheath that are found down the axon. 

Nodes of Ranvier

Multiple sclerosis (MS) is an autoimmune disorder characterized by the widespread loss of the myelin sheath on axons throughout the nervous system. This damage interferes with the electrical signal, preventing the rapid transmission of information between neurons. Symptoms can include dizziness, fatigue, loss of motor control, and sexual dysfunction. While treatments can help manage symptoms and modify the disease's course, there is currently no known cure for MS.

Multiple Sclerosis

Imagine two neurons of the same length are tasked with sending an electrical signal. Neuron A's axon is coated with a thick, fatty substance that acts as an insulator. Neuron B's axon lacks this coating. Which of the following statements most accurately predicts the functional difference between these two neurons?

Based on the provided scenario, which component of a neuron is most likely compromised, and how does its impairment lead to the observed symptoms?

Neural Signal Transmission Impairment

Phenylketonuria (PKU) is a genetic disorder that leads to a reduction in myelin and causes abnormalities in the white matter of cortical and subcortical brain structures. Because the myelin sheath acts as an essential insulator for axons, its loss severely impairs normal neural operations. Consequently, this myelin reduction is associated with significant neurological issues, including severe cognitive deficits, exaggerated reflexes, and seizures.

Neurological Effects of Phenylketonuria (PKU)

The myelin sheath is a fatty substance formed by glial cells that coats a neuron's axon. It functions as an insulator, which increases the speed at which electrical signals travel down the axon. This insulation is crucial for the normal operation of neurons, and its loss can severely impair nervous system function.

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The axon is a major extension that leads away from the neuron's soma, varying in length from a fraction of an inch to several feet. Its primary role is to conduct electrical signals from the cell body down to its end, where it connects with other neurons at the terminal buttons.

Axon

Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020, April 22). Psychology (2nd ed.). OpenStax. https://openstax.org/books/psychology-2e/pages/1-introduction

OpenStax Psychology (2nd ed.) Textbook

Terminal buttons are structures at the end of an axon that contain synaptic vesicles filled with neurotransmitters. When an action potential reaches these buttons, it triggers the vesicles to release their neurotransmitters, facilitating communication with other neurons across the synaptic cleft.

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