Search results
Results From The WOW.Com Content Network
The myelin sheath of long nerves was discovered and named by German pathological anatomist Rudolf Virchow [21] in 1854. [22] French pathologist and anatomist Louis-Antoine Ranvier later discovered the nodes, or gaps, in the myelin sheath that now bear his name.
In the PNS, myelin protein zero (MPZ or P0) has a similar role to that of PLP in the CNS in that it is involved in holding together the multiple concentric layers of glial cell membrane that constitute the myelin sheath. The primary lipid of myelin is a glycolipid called galactocerebroside. The intertwining hydrocarbon chains of sphingomyelin ...
A well-developed Schwann cell is shaped like a rolled-up sheet of paper, with layers of myelin between each coil. The inner layers of the wrapping, which are predominantly membrane material, form the myelin sheath, while the outermost layer of nucleated cytoplasm forms the neurilemma. Only a small volume of residual cytoplasm allows ...
The myelin sheath is not continuous but is segmented along the axon's length at gaps known as the nodes of Ranvier. In the peripheral nervous system the myelination of axons is carried out by Schwann cells. [1] Oligodendrocytes are found exclusively in the CNS, which comprises the brain and spinal cord.
In the central nervous system the myelin sheath is provided by another type of glial cell, the oligodendrocyte. Schwann cells myelinate a single axon. An oligodendrocyte can myelinate up to 50 axons. [18] The composition of myelin is different in the two types. In the CNS the major myelin protein is proteolipid protein, and in the PNS it is ...
Additionally, the volume of the sheath itself increases proportionately with the volume and surface area of the neuron's somata. The distance of extracellular space between the sheath and the neuronal plasma membrane measures 20 nanometres (7.9 × 10 −7 in), allowing the neuron and its SGC sheath to form a single anatomical and functional ...
The endoneurium (also called endoneurial channel, endoneurial sheath, endoneurial tube, or Henle's sheath) is a layer of delicate connective tissue around the myelin sheath of each myelinated nerve fiber in the peripheral nervous system. [1] Its component cells are called endoneurial cells. [2]
The neurilemma is underlain by the myelin sheath (also known as the medullary sheath). In the central nervous system , axons are myelinated by oligodendrocytes , thus lack neurilemma. The myelin sheaths of oligodendrocytes do not have neurilemma because excess cytoplasm is directed centrally toward the oligodendrocyte cell body.