News tagged with nerve fibers
Related topics: white matter , nerve cells , brain cells , central nervous system , multiple sclerosis
An axon or nerve fiber is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma.
An axon is one of two types of protoplasmic protrusions that extrude from the cell body of a neuron, the other type being dendrites. Axons are distinguished from dendrites by several features, including shape (dendrites often taper while axons usually maintain a constant radius), length (dendrites are restricted to a small region around the cell body while axons can be much longer), and function (dendrites usually receive signals while axons usually transmit them). All of these rules have exceptions, however.
Some types of neurons have no axon—these are called amacrine cells, and transmit signals from their dendrites. No neuron ever has more than one axon; however in invertebrates such as insects the axon sometimes consists of several regions that function more or less independently of each other. Most axons branch, in some cases very profusely.
Axons make contact with other cells—usually other neurons but sometimes muscle or gland cells—at junctions called synapses. At a synapse, the membrane of the axon closely adjoins the membrane of the target cell, and special molecular structures serve to transmit electrical or electrochemical signals across the gap. Some synaptic junctions appear partway along an axon as it extends—these are called en passant ("in passing") synapses. Other synapses appear as terminals at the ends of axonal branches. A single axon, with all its branches taken together, can innervate multiple parts of the brain and generate thousands of synaptic terminals.
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A study by researchers at Henry Ford Hospital found "substantial evidence" that a regenerative process involving damaged nerve fibers in the spinal cord could hold the key to better functional recovery by most stroke victims.
Neuroscience May 23, 2013 | 4 / 5 (1) | 0 |
(Medical Xpress)—Working with lab mice models of multiple sclerosis (MS), UC Davis scientists have detected a novel molecular target for the design of drugs that could be safer and more effective than current FDA-approved ...
Alzheimer's disease & dementia May 17, 2013 | 5 / 5 (2) | 0 |
By monitoring the behavior of a class of cells in the brains of living mice, neuroscientists at Johns Hopkins discovered that these cells remain highly dynamic in the adult brain, where they transform into ...
Neuroscience May 09, 2013 | 5 / 5 (2) | 0 |
(Medical Xpress)—Some parts of the body, like the liver, can regenerate themselves after damage. But others, such as our nervous system, are considered either irreparable or slow to recover, leaving thousands ...
Neuroscience May 13, 2013 | 5 / 5 (8) | 1 |
Scientists have identified an influential link in a chain of events that leads to autoimmune inflammation of the central nervous system in a mouse model of multiple sclerosis (MS).
Medical research May 02, 2013 | 5 / 5 (4) | 0 |
Scientists have identified a gene that keeps our nerve fibers from clogging up. Researchers in Ken Miller's laboratory at the Oklahoma Medical Research Foundation (OMRF) found that the unc-16 gene of the roundworm Caenorhabditis el ...
Genetics Apr 30, 2013 | not rated yet | 0