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Oligodendrocytes are a type of glial cell, non-neuronal cells in the central nervous system.They arise during development from oligodendrocyte precursor cells (OPCs), [8] which can be identified by their expression of a number of antigens, including the ganglioside GD3, [9] [10] [11] the NG2 chondroitin sulfate proteoglycan, and the platelet-derived growth factor-alpha receptor subunit (PDGF ...
In addition, oligodendrocytes possess two distinct types of microtubules: [22] Radial microtubules: They are located in the proximal regions of the ramified processes of oligodendrocytes, that extend outward from the cell body. Lamellar microtubules: They are the microtubules that eventually wrap around the axon, forming the myelin sheath.
Multiple pathways contribute to oligodendrocyte branching, but the exact molecular process by which oligodendrocytes extend and wrap around multiple axons remains incompletely understood. [28] Laminin , a component of the extracellular matrix , plays an important role in regulating oligodendrocyte production.
Oligodendrocytes are found in the CNS and resemble an octopus: they have bulbous cell bodies with up to fifteen arm-like processes. Each process reaches out to an axon and spirals around it, creating a myelin sheath. The myelin sheath insulates the nerve fiber from the extracellular fluid and speeds up signal conduction along the nerve fiber. [34]
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.
The proximal axons are able to regrow as long as the cell body is intact, and they have made contact with the Schwann cells in the endoneurium (also known as the endoneurial tube or channel). Human axon growth rates can reach 2 mm/day in small nerves and 5 mm/day in large nerves. [ 4 ]
Somatosensory receptors include senses such as pain, touch, temperature, itch, and stretch. For example, a specific muscle fiber called an intrafusal muscle fiber is a type of afferent neuron that lies parallel to the extrafusal muscle fibers thus functions as a stretch receptor by detecting muscle length. [2]
Remyelination is the process of propagating oligodendrocyte precursor cells to form oligodendrocytes to create new myelin sheaths on demyelinated axons in the Central nervous system (CNS). This is a process naturally regulated in the body and tends to be very efficient in a healthy CNS. [ 1 ]