Elastic fiber
Elastic fibers are part of the extracellular matrix in anatomy . They give the fabric elastic properties.
construction
Elastic fibers consist of two clearly distinguishable components, an elastin core and the microfibrils that surround it, which are made up of fibrillins and other proteins such as fibulin-5 . Fibulin-5 mediates the connection of the elastic fibers in the extracellular matrix with the surrounding cells by binding to integrins . Elastin is responsible for the name-giving property of elastic fibers. The individual elastin monomers are linked by covalent bonds via up to 4 lysine side chains and form random coil structures that play an important role in the elasticity of the elastic fibers.
Features and function
The elastic fibers have rubber-like properties. In addition to elasticity, they give the tissue mobility.
They can lengthen their original length by 150 percent by stretching, for example by contracting smooth muscle cells, and return to their original length when the force is gone. The tensile strength of the elastic fibers is around 300 N / cm². The resistance increases with increasing elongation.
If there are numerous elastic fibers in a fabric, they take on a yellowish color. A typical example is the “yellow band” ( ligamentum flavum ) that occurs between the vertebrae . The elasticity of the elastic fibers decreases with age. The greatest elasticity of the elastic fibers is at normal body temperature. At temperatures below 20 ° C, the elastic fibers change into a crystalline, glass-like structure, so that they become fragile.
The elastic fibers form three-dimensional networks and have a diameter between 0.2 and 5 micrometers.
Occurrence
Elastic fibers are found in many tissues. They are particularly numerous where elastic properties play an important role in the function of the organ or tissue. There are numerous elastic fibers in the skin , in elastic cartilage , in blood vessel walls, in lung tissue and in the vocal cords . The elastic fibers are formed by embryonic or juvenile fibroblasts and by smooth muscle cells .
histology
In histology , the elastic fibers are only visible with special stains. These include orcein , resorcinol fuchsin ( elastic staining according to Weigert ) and aldehyde fuchsin .
Individual evidence
- ↑ a b Luiz Carlos Uchôa Junqueira, Jose Carneiro: histology. Springer Verlag, 2004, ISBN 978-3540219651 , p. 63.
- ^ A b c Luiz Carlos Uchôa Junqueira, José Carneiro: Histology. Springer Verlag, 2004, ISBN 978-3540219651 , p. 64.
- ↑ a b c d Frans van den Berg: Applied Physiology. Georg Thieme Verlag, 2003, ISBN 978-3131160324 , p. 30.
- ↑ a b c d Theodor H. Schiebler, Horst-W. Korf: anatomy. Histology, history of development, macroscopic and microscopic anatomy, topography. Springer, 2007, ISBN 978-3798517707 , p. 39.