An extracellular matrix is a network of non-living tissue which provides support to cells. The extracellular matrix 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 an extracellular matrix from cellulose, while animals produce extracellular matrices with proteins, minerals, and certain carbohydrates.

The term “extracellular” literally means “outside the cell,” which tells you where the extracellular matrix is located. In some cases, the extracellular matrix 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 extracellular matrix simply 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 which keeps it elastic and strong. The skin's matrix also plays an important role in the healing process, as do extracellular matrices elsewhere in the body. This structure 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 which allow them to perform a variety of functions in the body. Tendons and ligaments have special proteins which 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 extracellular matrix.

Depending on the type of extracellular matrix involved, specific cells may be required to build it. Fibroblasts, for example, secrete the extracellular matrix which 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 they grow in. Cancers secrete certain enzymes which digest the extracellular matrix, 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 of the body. Without these enzymes, the cancer would not be able to penetrate the vulnerable tissue of the body.