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Wallerian degeneration is an active process of degeneration that results when a nerve fiber is cut or crushed and the part of the axon distal to the injury (which in most cases is farther from the neuron's cell body) degenerates. [1]
Axonotmesis of the nerve. Axonotmesis is an injury to the peripheral nerve of one of the extremities of the body. The axons and their myelin sheath are damaged in this kind of injury, but the endoneurium, perineurium and epineurium remain intact.
Wallerian degeneration is a process that occurs before nerve regeneration and can be described as a cleaning or clearing process that essentially prepares the distal stump for reinnervation. [2] Schwann cells are glial cells in the peripheral nervous system that support neurons by forming myelin that encases nerves.
During Wallerian degeneration, Schwann cells grow in ordered columns along the endoneurial tube, creating a band of Büngner cells that protects and preserves the endoneurial channel. Also, macrophages and Schwann cells release neurotrophic factors that enhance re-growth.
When the axon is torn, Wallerian degeneration, in which the part of the axon distal to the break degrades, takes place within one to two days after injury. [26] The axolemma disintegrates, [ 26 ] myelin breaks down and begins to detach from the cell in an anterograde direction (from the body of the cell toward the end of the axon), [ 27 ] and ...
Wallerian degeneration often occurs in the near the proximity of the injury site. [7] Neurapraxia is least serious form of nerve injury. [7] There are two different forms of mechanical nerve injury involving neurapraxia. The underlying causes of transient nerve injury typically include a brief ischemic episode or any form of compression. [5]
mildest type of nerve injury; sensory-motor problems present distal to the site of injury; intact endoneurium, perineurium, and the epineurium; wallerian degeneration not present; intact conduction in the distal and proximal segments, but no conduction across the injury [4] full nerve conduction recovery, requiring days to weeks
The optic radiation damage is composed by two factors: trans-synaptic degeneration, and wallerian degeneration [79] Respect the theory about the role of the meninges in MS evolution, it is important to notice that the optic nerve in its intraorbital part has the tree meninges and it is tightly coupled with the pia mater. [80]