GLOSSARY

The extracellular matrix (ECM) is a network of proteins and sugar molecules that fills the space between cells; besides providing a structural framework for tissues, it also influences cell communication and behavior.

Main Components

The matrix is made of two main parts: fibers and ground substance.
The fibers include collagen, which resists tension, and elastin, which provides elasticity; the ground substance is a watery gel made of proteoglycans, such as aggrecan in cartilage, and glycoproteins.
The composition of the matrix differs between tissues: in tendon it is rich in parallel collagen fibers, in cartilage it is rich in water-attracting proteoglycans, and in bone it is combined with calcium and phosphate minerals.