Elastic fiber
Elastic fibers have a component of the extracellular matrix. They impart elastic properties of the tissue.
Construction
Elastic fibers made from the polymer of elastin and elastic microfibrils which are composed of fibrillin and other proteins, such as fibulin -5. Fibulin -5 provides the connection of the elastic fibers in the extracellular matrix of the surrounding cells by binding to integrins. Elastin is responsible for the eponymous feature of the elastic fibers. The individual elastin monomers are linked by covalent bonds via a respective 4 - glycine side chains and form random coil structures, which play an important role in the elasticity of the elastic fibers.
Features and Function
The elastic fibers have rubber-like properties. In addition to flexibility, they give the tissue mobility.
You can extend its initial length by stretching, for example, by the contraction of smooth muscle cells to 150 percent and take the force is return to their original length. The tensile strength of the elastic fibers is about 300 N / cm ². The resistance increases with increasing strain.
Come elastic fibers in a fabric numerous before, these take on a yellowish color. As a typical example, the " Yellow Ribbon " ( ligamentum flavum ) is called that occurs between the vertebrae. The elasticity of the elastic fibers decreases with increasing age. The greatest elasticity of the elastic fibers occurs at normal body temperature. In less than 20 ° C, the elastic fibers pass into a crystalline, glassy structure, so that they are fragile.
The elastic fibers form three-dimensional networks, and have a diameter between 0.2 and 5 micrometers.
Occurrence
Elastic fibers are present in many tissues. Numerous they are mainly where elastic properties play an important role in the function of the organ or tissue. Elastic fibers are numerous in skin tissue, in the elastic cartilage, in vessel walls in the lung tissue and in the vocal cords. The elastic fibers are formed from embryonic or juvenile fibroblasts and smooth muscle cells.
Histology
In histology, the elastic fibers are visible only with special stains. These include orcein, resorcin-fuchsin ( Elastica staining by Weigert ) and Aldehydfuchsin.