What happens during Chromatolysis?
What happens during Chromatolysis?
Chromatolysis is a reactive change that occurs in the cell body of damaged neurons, involving the dispersal and redistribution of Nissl substance (rough endoplasmic reticulum and polyribosomes) in order to meet an increased demand for protein synthesis such as is required to regenerate axons.
What is the purpose of Chromatolysis?
Chromatolysis is the dissolution of the Nissl bodies in the cell body of a neuron. It is an induced response of the cell usually triggered by axotomy, ischemia, toxicity to the cell, cell exhaustion, virus infections, and hibernation in lower vertebrates.
What is meant by Chromatolysis?
: the dissolution and breaking up of chromophil material (such as chromatin) of a cell and especially a nerve cell.
What is central Chromatolysis?
Central chromatolysis (arrow) occurs when the normal aggregations of rough endoplasmic reticulum and associated ribosomes, known as Nissl substance, in the neuronal perikaryon disperse as a response to injury. It signifies the acceleration of neuronal protein synthesis in the face of cellular injury.
What is the Wallerian degeneration?
Wallerian degeneration is an active process of retrograde degeneration of the distal end of an axon that is a result of a nerve lesion. It occurs between 7 to 21 days after the lesion occurs. After the 21st day, acute nerve degeneration will show on the electromyograph.
What is anterograde degeneration?
Anterograde degeneration occurs when the axon distal to the site of injury degenerates. This usually begins within 24 hours and completes within 7 days of insult. The proximal part of the axon, still connected to the cell body, remains normal in appearance and function for 3–4 weeks.
Where are Schwann cells found?
peripheral nervous system
Schwann cells and satellite glia are the two main glial cell types of the peripheral nervous system (PNS). Whereas satellite glia are found within ganglia in close association with neuronal somata, Schwann cells are found in close contact with axons in the peripheral nerves.
What is retrograde degeneration?
Wallerian degeneration is a phenomenon that occurs when nerve fiber axons are damaged. A similar but distinct phenomenon known as retrograde degeneration occurs when the axon degenerates proximal to the injury. This backwards degeneration leads to disruption of the cell body and cell death.
What triggers Wallerian degeneration?
Any lesion of the axons that leads to an interruption and any lesion of the nerve cell bodies that leads to the cell death is followed by Wallerian degeneration. In the CNS common causes are infarction, hemorrhage, tumors, and head injury with shearing of nerve fibers.
Is Wallerian degeneration good or bad?
The mutation causes no harm to the mouse. The only known effect is that the Wallerian degeneration is delayed by up to three weeks on average after injury of a nerve.
What is the major difference between anterograde degeneration and retrograde degeneration?
Retrograde degeneration occurs when the proximal segment starts to degenerate and all affected RGCs die by 6–8 weeks. Ascending optic atrophy is characterized by degeneration of the RGC axons at the level of the optic nerve head by the anterograde mechanism.