The myelin is located in the nervous system, forming pods that are responsible for surrounding the axons of neurons. It is a system of phospholipid bilayers made up of sphingolipid, which enables the transmission of nerve impulses to the various body regions through an isolating effect.
Myelin is a sphingophospholipid that is formed by sphingol, an alcohol made up of a chain of choline, phosphate and fatty acid. In the spinal and cranial nerves, as well as the peripheral nervous system (PNS), myelin sheaths are formed by the Schwann cells that produce layers of proteins and lipids.
It is in the membrane of this class of small-volume cells that myelin is found: since Schwann cells successively coiled into axons, giving rise to sheaths.
The myelin sheath is responsible for wrapping the axon with the exception of the Ranvier’s nodules (which are those places located between the myelin sheaths). Myelin functions as an electrochemical insulator that allows nerve impulses to jump from node to node.
The situation within the central nervous system (CNS) is different since, in this case, myelin is made up of oligodendrocytes (Another class of cells that have numerous dendrites).
It is common to talk about “White matter” Y “Gray matter” in the brain. Myelin is responsible for the color of white matter, while non-myelinated axons make up gray matter.
If a person loses myelin due to some disorder, they will suffer from great problems in their nervous system. The electrical impulses, in the absence of this substance, will not complete their course or will circulate very slowly, as occurs with diseases as the multiple sclerosis.
However, it must also be emphasized that in addition to this aforementioned disease, others may occur in the patient, such as amyotrophic lateral sclerosis, also called Charcot’s disease, which is characterized by being degenerative in nature and which translates into a progressive muscle paralysis that ends in death.
Similarly, other diseases caused by myelin are Baló’s concentric sclerosis, which is neurological in nature and occurs as a consequence of the rapid loss of the envelope that covers said myelin, or leukodystrophies. The latter in particular also occur as a result of the degeneration of the fat of the former and among its most frequent symptoms are visual or motor class alterations.
And all this, without forgetting that there are other pathologies that are also directly related to myelin. This would be the case of central pontine myelinolysis, Devic syndrome or Marchiafava-Bignami disease. Corpus callosum atrophy syndrome is also known as the latter pathology, which is a very rare encephalopathy.
People with chronic alcoholism are the ones who can be most affected by this disease, which results in a series of symptoms such as changes in personality, seizures, hallucinations, changes in the voice, or notable deficiencies in intelligence. However, we can establish that there are two clearly differentiated types: the one in which the damage is slight and the one in which the patient reaches a coma or even suffers a state of stupor.