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Oligodendrocytes – Location, Structure, and Function

  • Another type of support cell found in the spinal cord and brain (CNS) is the image descriptionoligodendrocyte.
An image showing the Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
An image showing the Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
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  • As its name implies, an oligodendrocyte is a cell (cyte) with a relatively small number (oligo) of image descriptioncytoplasmic processes that branch (dendro) from a spherical cell body.
An image showing the Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
An image showing the Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
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  • The tip of each cytoplasmic process repeatedly wraps around a nearby axon to form a lipid-rich image descriptionmyelin sheath measuring about 1 millimeter in length.
An image showing the Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
An image showing the Myelin sheath in addition to Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
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  • Oligodendrocytes thus function much like Schwann cells do in the PNS.
  • However, oligodendrocytes have multiple cytoplasmic processes and myelinate several (up to 50) image descriptionaxons at the same time.
An image showing the Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
An image showing the Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
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  • As in the PNS, the narrow gaps between myelin sheaths are called image descriptionnodes of Ranvier, and action potentials (electro-chemical impulses) occur only in these unmyelinated regions of the axon.
An image showing the Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
An image showing the Node of Ranvier in addition to Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
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  • The image descriptionjumping of action potentials from node to node (saltatory conduction) increases the rate at which signals move down the axon.
An image showing the Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
An image showing the jumping of Action potentials from node to node in addition to Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
An image showing the jumping of Action potentials from node to node in addition to Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
An image showing the jumping of Action potentials from node to node in addition to Oligodendrocytes giving branches to neurons axons through its Cytoplasmic processes in the white matter
  • Because lipids are light in color, they make myelinated axons appear white in their natural (unstained) state.
  • The regions of the CNS that contain high concentrations of myelinated axons are thus referred to as white matter.