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Myelin's best known function is to increase the rate at which information, encoded as electrical charges, passes along the axon's length. Myelin achieves this by eliciting saltatory conduction. [1] Saltatory conduction refers to the fact that electrical impulses 'jump' along the axon, over long myelin sheaths, from one node of Ranvier to the next.
In the first group, a healthy and normal myelin is destroyed by toxic substances, chemicals, or autoimmune reactions. In the second group, the myelin is inherently abnormal and undergoes degeneration. [6] The Poser criteria named this second group dysmyelinating diseases. [7]
Inflammatory demyelinating diseases (IDDs), sometimes called Idiopathic (IIDDs) due to the unknown etiology of some of them, are a heterogenous group of demyelinating diseases - conditions that cause damage to myelin, the protective sheath of nerve fibers - that occur against the background of an acute or chronic inflammatory process.
In the first group a normal and healthy myelin is destroyed by a toxic, chemical or autoimmune substance. In the second group, myelin is abnormal and degenerates. [1] The second group was denominated dysmyelinating diseases by Poser [2] Therefore, since Poser demyelinating diseases normally refers to the myelinoclastic part.
Myelin sheath of a healthy neuron in the central nervous system. Multiple sclerosis is an inflammatory demyelinating disease of the CNS in which activated immune cells invade the central nervous system and cause inflammation, neurodegeneration, and tissue damage. The underlying cause is currently unknown.
Myelitis damages the myelin sheath that wraps the axon. MRI image of transverse myelitis patient's spinal cord. Myelitis lesions usually occur in a narrow region but can be spread and affect many areas. Acute flaccid myelitis: a polio-like syndrome that causes muscle weakness and paralysis.
The oligodendrocytes that originally formed a myelin sheath cannot completely rebuild a destroyed myelin sheath. However, the central nervous system can recruit oligodendrocyte stem cells capable of proliferation and migration and differentiation into mature myelinating oligodendrocytes. The newly formed myelin sheaths are thinner and often not ...
Central pontine myelinolysis is a neurological condition involving severe damage to the myelin sheath of nerve cells in the pons (an area of the brainstem). It is predominately iatrogenic (treatment-induced), and is characterized by acute paralysis, dysphagia (difficulty swallowing), dysarthria (difficulty speaking), and other neurological symptoms.