Extracellular matrix, SEM

Extracellular matrix (ECM) produced by dermal fibroblasts, scanning electron micrograph (SEM). The ECM is a complex structural tissue component surrounding and supporting cells in mammalian tissues. It is composed of 3 major classes of biomolecules: 1) Structural proteins - collagen and elastin, 2) Specialized proteins - such as: fibrillin, fibronectin, and laminin and 3) Proteoglycans - complex proteins and long chains of repeating disaccharide units called glycosaminoglycans (GAGs, such as: hyaluronic acid, chondroitin sulphate, heparin, heparan sulphate). Collagen is the major protein comprising the ECM. Many cells bind to components of the extracellular matrix. The cell to ECM adhesion is regulated by specific cell surface cellular adhesion molecules (CAM) known as integrins. The integrins transmit mechanical stimuli from the ECM to the cytoskeleton. Magnification: x1,000 when shortest axis printed at 25 millimetres.