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When a peripheral fiber is severed, the myelin sheath provides a track along which regrowth can occur. However, the myelin layer does not ensure a perfect regeneration of the nerve fiber. Some regenerated nerve fibers do not find the correct muscle fibers, and some damaged motor neurons of the peripheral nervous system die without regrowth.
Transmission electron micrograph of a myelinated axon Neuron with oligodendrocyte and myelin sheath showing cytoskeletal structures at a node of Ranvier. The basic helix–loop–helix transcription factor OLIG1 plays an integral role in the process of oligodendrocyte myelinogenesis by regulating expression of myelin-related genes. OLIG1 is ...
Aδ fibers carry information from peripheral mechanoreceptors and thermoreceptors to the dorsal horn of the spinal cord. This pathway describes the first-order neuron. Aδ fibers serve to receive and transmit information primarily relating to acute pain (sharp, immediate, and relatively short-lasting). This type of pain can result from several ...
A well-developed Schwann cell is shaped like a rolled-up sheet of paper, with layers of myelin between each coil. The inner layers of the wrapping, which are predominantly membrane material, form the myelin sheath, while the outermost layer of nucleated cytoplasm forms the neurilemma. Only a small volume of residual cytoplasm allows ...
White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system. The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons). This myelin is found in almost all long nerve fibers, and acts as an electrical insulation.
Nervous tissue, also called neural tissue, is the main tissue component of the nervous system.The nervous system regulates and controls body functions and activity. It consists of two parts: the central nervous system (CNS) comprising the brain and spinal cord, and the peripheral nervous system (PNS) comprising the branching peripheral nerves.
The myelin sheath is a multi-layered membrane, unique to the nervous system, that functions as an insulator to greatly increase the efficiency of axonal impulse conduction. [ 2 ] In humans, point mutations in PLP are the cause of Pelizaeus–Merzbacher disease (PMD), a neurologic disorder of myelin metabolism.
Spontaneous myelin repair was first observed in cat models. [49] It was later discovered to occur in the human CNS as well, specifically in cases of multiple sclerosis (MS). [50] Spontaneous myelin repair does not result in morphologically normal oligodendrocytes and is associated with thinner myelin compared to axonal diameter than normal ...