Extracellular matrix

In biology, extracellular matrix (ECM) is any material part of a tissue but not part of any cell. Extracellular matrix is the defining feature of connective tissue.

ECM can be made up of proteins such as collagen, fibrin and elastin[?]; minerals such as hydroxyapatite[?]; or fluids such as blood plasma. Given this diversity, it can serve any number of functions.