unmyeliiniset
Unmyelinated fibers, also known as unmyelinated axons, are nerve fibers that lack the myelin sheath, a fatty substance that forms a protective layer around the axon of many neurons. This sheath is crucial for the efficient transmission of electrical signals along the length of the axon. In unmyelinated fibers, the electrical impulse travels more slowly and less efficiently compared to myelinated fibers. Unmyelinated fibers are typically found in the peripheral nervous system, particularly in sensory neurons and in the central nervous system, they are more commonly found in the brainstem and spinal cord.
The absence of the myelin sheath in unmyelinated fibers allows for a more direct and continuous transmission
Unmyelinated fibers are also more susceptible to damage and degeneration compared to myelinated fibers. This is