An extracellular matrix is a network of non-living tissue that provides support to cells. It also performs a number of other very specific functions, depending on the types of cells it is associated with, and it takes many forms. The constituent materials in this structure can vary widely; plants, for example, build them from cellulose, while animals produce extracellular matrices with proteins, minerals, and certain carbohydrates.
The term “extracellular” literally means “outside the cell,” which explains where the matrix is located. In some cases, it is actually secreted by the surrounding cells. In bone, for example, a mineralized extracellular matrix is designed to provide support and resist compression. In some cases, the matrixsimply fills up the space between different types of tissue, ensuring that they are kept separate and that their functions are not disturbed.
The skin has an extensive extracellular matrix that keeps it elastic and strong. The skin's matrix also plays an important role in the healing process, as do such structures elsewhere in the body. It can also help to regulate communication between cells and the production of certain substances in the body. In addition, it provides a framework for cell adhesion, encouraging growth and stable healing.
Bones, muscles, and tendons all have extensive extracellular matrices that allow them to perform a variety of functions in the body. Tendons and ligaments have special proteins that allow them to be stretched and contracted so that the body can be moved, while bone is made primarily from collagen and mineral deposits, creating a very solid, secure structure.
Depending on the type of extracellular matrix is involved, specific cells may be required to build it. Fibroblasts, for example, secrete the matrix that creates fibrous connective tissue, while osteoblasts make new bone. When these cells are disrupted in some way, it can cause serious problems, as the body constantly reabsorbs the substances it makes even as it produces more; if no more is being produced, or the matrix is being overproduced, it can cause health conditions.
When cancers attack the body, one of the things they assault first is the extracellular matrix in the region where they grow. Cancers secrete certain enzymes that digest the structure, providing a direct link with the tissue beneath it and allowing the cancer to metastasize as it breaks up and distributes cells to new regions. Without these enzymes, the cancer would not be able to penetrate the vulnerable tissue of the body.