Anatomy & Physiology: The Unity of Form and Function, 7th Edition

Published by McGraw-Hill Education
ISBN 10: 0073403717
ISBN 13: 978-0-07340-371-7

Chapter 12 - Section 12.2 - Study Guide - Assess Your Learning Outcomes - Page 471: 5

Answer

Neurons transport various substances between the neurosoma (cell body) and the distal ends of the axon using several mechanisms and structures. These transport processes are essential for maintaining the health and function of the neuron, particularly over long distances. There are two main modes of neuronal transport: 1. **Anterograde Transport:** - **Direction:** Anterograde transport refers to the movement of cellular materials from the neurosoma (cell body) toward the distal ends of the axon, including the axon terminals. - **Mechanism:** Anterograde transport relies heavily on molecular motor proteins known as kinesins. These motor proteins move along microtubules, which are part of the neuron's cytoskeleton. Kinesins carry various cargo, including organelles, proteins, and vesicles filled with neurotransmitters. - **Function:** Anterograde transport ensures that essential materials produced in the cell body, such as proteins and neurotransmitters, reach the axon terminals, where they can be used for synaptic communication and maintenance. 2. **Retrograde Transport:** - **Direction:** Retrograde transport involves the movement of cellular materials from the distal ends of the axon, such as axon terminals, back toward the neurosoma (cell body). - **Mechanism:** Retrograde transport primarily relies on another class of motor proteins called dyneins. Dyneins move in the opposite direction of kinesins, traveling along microtubules in the axon. They transport various substances, including endocytosed molecules, signaling molecules, and cellular waste products, back to the cell body. - **Function:** Retrograde transport is crucial for recycling and degrading materials, as well as for receiving important signals from the axon terminals. It helps neurons maintain their health by removing damaged or unnecessary components and responding to synaptic input. These transport processes are essential for the proper functioning of neurons, especially given the long distances that some axons can span in the nervous system. Neurons must continually transport materials to maintain the integrity of their axons and ensure efficient communication with other neurons and target cells at synapses. Dysregulation of these transport mechanisms can lead to neuronal dysfunction and neurodegenerative diseases.

Work Step by Step

Neurons transport various substances between the neurosoma (cell body) and the distal ends of the axon using several mechanisms and structures. These transport processes are essential for maintaining the health and function of the neuron, particularly over long distances. There are two main modes of neuronal transport: 1. **Anterograde Transport:** - **Direction:** Anterograde transport refers to the movement of cellular materials from the neurosoma (cell body) toward the distal ends of the axon, including the axon terminals. - **Mechanism:** Anterograde transport relies heavily on molecular motor proteins known as kinesins. These motor proteins move along microtubules, which are part of the neuron's cytoskeleton. Kinesins carry various cargo, including organelles, proteins, and vesicles filled with neurotransmitters. - **Function:** Anterograde transport ensures that essential materials produced in the cell body, such as proteins and neurotransmitters, reach the axon terminals, where they can be used for synaptic communication and maintenance. 2. **Retrograde Transport:** - **Direction:** Retrograde transport involves the movement of cellular materials from the distal ends of the axon, such as axon terminals, back toward the neurosoma (cell body). - **Mechanism:** Retrograde transport primarily relies on another class of motor proteins called dyneins. Dyneins move in the opposite direction of kinesins, traveling along microtubules in the axon. They transport various substances, including endocytosed molecules, signaling molecules, and cellular waste products, back to the cell body. - **Function:** Retrograde transport is crucial for recycling and degrading materials, as well as for receiving important signals from the axon terminals. It helps neurons maintain their health by removing damaged or unnecessary components and responding to synaptic input. These transport processes are essential for the proper functioning of neurons, especially given the long distances that some axons can span in the nervous system. Neurons must continually transport materials to maintain the integrity of their axons and ensure efficient communication with other neurons and target cells at synapses. Dysregulation of these transport mechanisms can lead to neuronal dysfunction and neurodegenerative diseases.
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