axon

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Related to axonal: Axonal transport, axonal degeneration, axonal neuropathy

axon:

see nervous systemnervous system,
network of specialized tissue that controls actions and reactions of the body and its adjustment to the environment. Virtually all members of the animal kingdom have at least a rudimentary nervous system.
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; synapsesynapse
, junction between various signal-transmitter cells, either between two neurons or between a neuron and a muscle or gland. A nerve impulse reaches the synapse through the axon, or transmitting end, of a nerve cell, or neuron.
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.

Axon

 

a neurite, or axis cylinder; the process of a nerve cell along which neural impulses proceed from the cell body to innervated organs and other nerve cells.

Only one axon branches off each neuron, or nerve cell. The nutrition and growth of the axon depends on the neuron body; upon transection of the axon, its peripheral portion dies, but the central portion preserves its viability. Large animals possess axons—for example, those proceeding from the spinal cord to the extremities—that may reach a length of one meter or more when their diameter is several millimicrons (mμ). In some animals—for example, squid and fish—huge axons are found which measure hundreds of mμ in thickness. In axoplasm—that is, the protoplasm of axons—there are extremely thin fibrils, known as neurofibrils, as well as mitochondria and the endoplasmic network. Depending on whether axons are covered with a myelic (fatty) membrane or not, they are known as medullated or nonmedullated nerve fibers. The structure of the membranes and the diameters of the axons that constitute the nerve fiber are the factors that determine the rate of stimulus transmission along the nerve. The terminal sections of the axon, or terminals, branch off and make contact with other nerve, muscle, and gland cells. Stimuli are transmitted through these contact points, which are known as synapses. A nerve is a collection of axons.

axon

[′ak‚sän]
(neuroscience)
The process or nerve fiber of a neuron that carries the unidirectional nerve impulse away from the cell body. Also known as neuraxon; neurite.
References in periodicals archive ?
We included 17 axonal neuropathy (AN) patients, 11 vasculitic neuropathy (VN) patients and 12 hereditary neuropathy with liability to pressure palsy (HNPP) who had undergone sural and superficial peroneal nerve biopsy as part of the diagnostic work-up of their neuropathy and whose nerve biopsy specimens were suitable for the immunohistochemical analysis.
This was much faster than could be expected in typical GBS patients who have significant changes, both demyelinating and axonal, on NCS/EMG.
Three different types of CMT disease are distinguished based on the abnormality that disrupts the nerve function: the demyelinating type (CMT1), the axonal type (CMT2), and an intermediate type.
Depending on the location of edema and/or hemorrhage, one should be able to make the diagnosis of diffuse axonal injury--a diagnosis which has critical prognostic implications due
Single nucleotide polymorphisms] associated previously with different psychiatric disorders identified convergence of pathways in synaptogenesis axonal guidance, and synaptic plasticity; and now calcium signaling, which is pivotal in the mechanisms of all these biological processes.
The EMG studies in these patients however, suggests an axonal polyradiculoneuropathy, as opposed to the typical demyelinating picture seen with GBS.
Although histologic examination of clinically affected human peripheral nerves in cases of CO intoxication has shown demyelination with preservation of axons (5), Choi (7), from his electrophysiological studies suggested a concomitant axonal involvement.
The latter has been used to detect axonal injury, a type of neuronal damage that occurs during a concussion.
These behavior disorders have different patterns of brain involvement in different parts of brain (4,5) Diffuse axonal injury (DAI) is one of the most common and important pathologic features of traumatic brain injury (6).
When administered after femoral nerve transection and surgical repair in rats, as little as 1 h of ES accelerates axonal growth across the injury site, thereby reducing the time needed for motoneurons to reinnervate muscles [11].
The GBS patients were classified into different subgroups according to their clinical presentation and comprised of 28 patients with acute inflammatory demyelinating polyneuropathy (AIDP), 23 with acute motor axonal neuropathy (AMAN) and 8 with acute motor sensory axonal neuropathy (AMSAN).