Final answer:
The statement is True; myelin sheaths around an axon substantially increase the conduction velocity of nerve impulses through saltatory conduction, where action potentials jump from node to node.
Step-by-step explanation:
True or False: The layered sections of myelin along the length of an axon affect a substantial increase in the conduction velocity of a nerve impulse. The statement is True.
The presence of myelin sheaths in the nervous system enhances the speed at which electrical signals are transmitted along an axon. The myelination provides insulation, much like the plastic or rubber around electrical wires, preventing signal loss and allowing the electric impulses to move more efficiently. The nodes of Ranvier are the unmyelinated gaps between the myelinated sections of the axon, which are essential for saltatory conduction. This is where the action potentials are actively regenerated, effectively jumping from node to node rather than traveling continuously along the axon, thereby speeding up the overall conduction of the nerve impulse.
Diseases such as multiple sclerosis demonstrate the importance of the myelin sheath, as the degeneration of myelin leads to impaired nerve signal transmission and various neurological symptoms. Apart from myelination, the axon's diameter also influences the speed of conduction, similar to how water flows faster in a broader river compared to a narrow stream.