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Neurology. 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] A related process of dying back or retrograde degeneration known as 'Wallerian-like degeneration ...
Slower degeneration of the distal segment than that which occurs in the peripheral nervous system also contributes to the inhibitory environment because inhibitory myelin and axonal debris are not cleared away as quickly. All these factors contribute to the formation of what is known as a glial scar, which axons cannot grow across. [9]
The three models explaining synaptic pruning are axon degeneration, axon retraction, and axon shedding. In all cases, the synapses are formed by a transient axon terminal, and synapse elimination is caused by the axon pruning. Each model offers a different method in which the axon is removed to delete the synapse.
The white space represents a disruption of the nerve fibers, resulting in a loss of nerve supply to the muscle fibers. Denervation is any loss of nerve supply regardless of the cause. If the nerves lost to denervation are part of the neuronal communication to a specific function in the body then altered or a loss of physiological functioning ...
A neurodegenerative disease is caused by the progressive loss of neurons, in the process known as neurodegeneration. [2][3] Neuronal damage may also ultimately result in their death. Neurodegenerative diseases include amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, Alzheimer's disease, Huntington's disease, multiple ...
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 ...
An axon (from Greek ἄξων áxōn, axis) or nerve fiber (or nervefibre: see spelling differences) is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different ...
Nerve injury classification assists in prognosis and determination of treatment strategy for nerve injuries. Classification was described by Seddon in 1943 and by Sunderland in 1951. [1] In the lowest degree of nerve the nerve remains intact, but signaling ability is damaged, termed neurapraxia. In the second degree the axon is damaged, but the ...