Biomaterial Database

Membrane junctions in the myelin sheath of goldfish lateral nerve. 1978

W S Bertaud

The myelin sheath of the goldfish lateral line nerve has been studied by means of the freeze-etch technique. Fracture faces of the myelin lamellae reveal linear structural elements which in some respects resemble those of tight junctions. In unfixed myelin rows of particles on the ef face are matched by narrow grooves on the pf face. Fixation with glutaraldehyde produces a partitioning of junctional particles between the 2 fracture faces. These elements are observed most frequently in the outer layers of the sheath where their arrangement is predominantly more or less parallel and longitudinal, merging in places into a more reticulate organization. They also occur at other levels in the myelin and in association with Schmidt-Lantermann clefts. Orientation in these cases appears to be predominantly longitudinal, though circumferentially running elements have been observed. The possible functional significance of these structures and their implications for tissue development, maintenance and growth are discussed.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009186	Myelin Sheath	The lipid-rich sheath surrounding AXONS in both the CENTRAL NERVOUS SYSTEMS and PERIPHERAL NERVOUS SYSTEM. The myelin sheath is an electrical insulator and allows faster and more energetically efficient conduction of impulses. The sheath is formed by the cell membranes of glial cells (SCHWANN CELLS in the peripheral and OLIGODENDROGLIA in the central nervous system). Deterioration of the sheath in DEMYELINATING DISEASES is a serious clinical problem.	Myelin,Myelin Sheaths,Sheath, Myelin,Sheaths, Myelin
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D003530	Cyprinidae	A family of freshwater fish comprising the minnows or CARPS.	Barbels,Chub,Dace,Minnows,Roach (Fish),Shiner,Tench,Tinca,Barbus,Rutilus rutilus,Tinca tinca,Chubs,Shiners,Tinca tincas,tinca, Tinca
D005613	Freeze Etching	A replica technique in which cells are frozen to a very low temperature and cracked with a knife blade to expose the interior surfaces of the cells or cell membranes. The cracked cell surfaces are then freeze-dried to expose their constituents. The surfaces are now ready for shadowing to be viewed using an electron microscope. This method differs from freeze-fracturing in that no cryoprotectant is used and, thus, allows for the sublimation of water during the freeze-drying process to etch the surfaces.	Etching, Freeze
D006054	Goldfish	Common name for Carassius auratus, a type of carp (CARPS).	Carassius auratus
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia