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Myelin is formed by oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system.Therefore, the first stage of myelinogenesis is often defined as the differentiation of oligodendrocyte progenitor cells (OPCs) or Schwann cell progenitors into their mature counterparts, [4] followed by myelin formation around axons.
However, the myelin layer does not ensure a perfect regeneration of the nerve fiber. Some regenerated nerve fibers do not find the correct muscle fibers, and some damaged motor neurons of the peripheral nervous system die without regrowth. Damage to the myelin sheath and nerve fiber is often associated with increased functional insufficiency.
Once an axon is degenerated, it cannot regenerate like myelin, thus making research to promote remyelination that much more important. MS is more severe in some people than others, most likely from their family genetics and the way that genes are expressed within them. [6] The overall cause for multiple sclerosis itself is completely unknown.
Nervous system injuries affect over 90,000 people every year. [2] Spinal cord injuries alone affect an estimated 10,000 people each year. [ 3 ] As a result of this high incidence of neurological injuries, nerve regeneration and repair, a subfield of neural tissue engineering , is becoming a rapidly growing field dedicated to the discovery of ...
Schwann cells or neurolemmocytes (named after German physiologist Theodor Schwann) are the principal glia of the peripheral nervous system (PNS). Glial cells function to support neurons and in the PNS, also include satellite cells, olfactory ensheathing cells, enteric glia and glia that reside at sensory nerve endings, such as the Pacinian corpuscle.
White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system. The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons). This myelin is found in almost all long nerve fibers, and acts as an electrical insulation.
These cells do so by somal translocation. Neurons migrating with this mode of locomotion are bipolar and attach the leading edge of the process to the pia . The soma is then transported to the pial surface by nucleokinesis , a process by which a microtubule "cage" around the nucleus elongates and contracts in association with the centrosome to ...
The insulation must be proportional to the diameter of the fibre inside. The optimal ratio of axon diameter divided by the total fiber diameter (which includes the myelin) is 0.6. [24] Oligodendrocytes in rat cerebellum stained with antibody to myelin basic protein in red and for DNA in blue. Two oligodendrocyte cell bodies are clearly visible ...