Myelin incisure

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Myelin incisure
Diagram of longitudinal sections of medullatednerve fibers. (Incisure labeled at upper left.)
Identifiers
Code	TH H2.00.06.2.03015
Dorlands /Elsevier	12447772
Anatomical terminology [edit on Wikidata]

Myelin incisures (a.k.a. Schmidt-Lanterman clefts, Schmidt-Lanterman incisures, clefts of Schmidt-Lanterman, segments of Lanterman, medullary segments), are small pockets of cytoplasm left behind during the Schwann cell mylenation process. They arehistological evidence of the small amount of cytoplasm that remains in the inner layer of the myelin sheath created by Schwann cellswrapping tightly around a nerve.

In the peripheral nervous system (PNS) axons can be either myelinated or unmyelinated. Myelination refers to the insulation of an axon with concentric surrounding layers of lipid membrane (myelin) produced by Schwann cells. These layers are generally uniform and continuous (similar in structure to a fruit roll up), but due to imperfect nature of the process by which Schwann cells wrap the nerve axon, this wrapping process can sometimes leave behind small pockets of residual cytoplasm displaced to the periphery during the formation of the myelin sheath. These pockets, or "incisures", can subdivide the myelinated axon into irregular portions. These staggered clefts also provide communication channels between layers by connecting the outer collar of cytoplasm of the Schwann cell to the deepest layer of myelin sheath.

References[edit]

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

External links[edit]

• Histology image: 22801loa – Histology Learning System at Boston University

[hide] v t e Nervous tissue CNS Tissue Types Grey matter White matter  Projection fibers Association fiber Commissural fiber Lemniscus Funiculus Fasciculus Decussation Commissure   Neuropil Meninges Cell Types Neuronal Pyramidal Purkinje Granule Glial insulating: Myelination: Oligodendrocyte other Astrocyte  Radial glial cell   Ependymal cells  Tanycyte   Microglia PNS General Posterior  Root Ganglion Ramus   Anterior  Root Ramus   Ramus communicans  Gray White   Autonomic ganglion (Preganglionic nerve fibers Postganglionic nerve fibers) Connective tissues epineurium perineurium endoneurium nerve fascicle Neuroglia Myelination: Schwann cell  Neurolemma Myelin incisure Node of Ranvier Internodal segment   Satellite glial cell Neurons/ nerve fibers Parts Soma Axon hillock Axon Axon terminals Axoplasm Axolemma Neurofibril/neurofilament Dendrite Nissl body Dendritic spine Apical dendrite/Basal dendrite Types Bipolar Unipolar Pseudounipolar Multipolar Interneuron  Renshaw Afferent nerve fiber/ Sensory nerve GSA GVA SSA SVA fibers  Ia Ib or Golgi II or Aβ III or Aδ or fast pain IV or C or slow pain Efferent nerve fiber/ Motor nerve GSE GVE SVE Upper motor neuron Lower motor neuron  α motorneuron β motorneuron γ motorneuron Termination Synapse Electrical synapse/Gap junction Chemical synapse  Synaptic vesicle Active zone Postsynaptic density   Ribbon synapse Neuromuscular junction Sensory receptors Meissner's corpuscle Merkel nerve ending Pacinian corpuscle Ruffini ending Muscle spindle Free nerve ending Olfactory receptor neuron Photoreceptor cell Hair cell Taste bud