![]() List of abbreviations |
Vocabulary
of micros- copic anatomy specialist terms explained in English + German |
![]() Every attempt was made to provide correct information and labelling, however any liability for eventual errors or incompleteness is rejected! |
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non-myelinated nerve
Schwann cell (rat) |
non-myelinated nerve fibres in a
Schwann cell, colon (rat) |
myelinated nerve fibre +
Schwann cell (monkey) |
myelinated nerve fibre
+ Schwann cell 2 (rat) |
myelinated nerve fibre
Schwann cell 1 (rat) |
myelinsheath of a fibre in vestibulo-
cochlear nerve (guinea pig) |
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myelinated and non-my-
elinated axons (monkey) |
myelinated and non-myelinated nerve
fibres in the nervus vagus esophagus (rat) |
detail thereof | inner + outer mesaxon on
myelin sheath (monkey) |
detail 1: inner mes-
axon (monkey) |
detail 2: outer
mesaxon (monkey) |
Schwann cells (Terminologia histologica: Gliocyti peripherici;
Neurolemmocyti) form the myelin sheaths (Terminologia histologica:
Stratum myelini) in peripherical (= nerve tissue apart from CNS,
i.e. apart from brain and spinal cord) myelinated
nerves
and wrap the non-myelinated nerve cell processes (axons or dendrites) with
one layer of their cell membrane and
cytoplasm. Schwann cells
nutrify
and insulate the axons (impulse conducting
processes of nerve cells to other cells)
as well as dendrites (impulse receiving
processes of nerve cells) of nerves.
They may have a length of
over 100 µm. The myelin
sheath is formed by multiple, often far over 20 layers of closely attached
cell membrane of a Schwann cell. The outer
mesaxon (Terminologia histologica: Mesaxon externum) is the connection
of the outer cell membrane to the compact
myelin sheath. The inner mesaxon
(Terminologia histologica: Mesaxon internum) is the connection between
the myelin sheath and the inner part of the cell
membrane of the Schwann cell which is directly opposite the axolemm,
i.e. the cell membrane of the nerve fibre
ensheated by the Schwann cell.
At the border between two neighbouring Schwann cells a myelin sheath
gap called node of Ranvier (Terminologia
histologica: Nodi interruptionis myelini) is formed along the related nerve
fibre. The nodes of Ranvier are the morphological base for saltatory
impulse transduction which is very fast. Further, there are Schmidt-Lanterman
incisures (Terminologia histologica: Incisura myelini), oblique
interruptions of the myelin sheath, i.e. myelin clefts or incisures where
some Schwann cell cytoplasm is present
between the myelin layers.
--> classification of nerve
fibres
--> nerve, nerve
tissue, central nervous system
--> Electron microscopic atlas Overview
--> Homepage of the workshop
Ten images were kindly provided by Prof. H. Wartenberg;
other images, page & copyright H. Jastrow.