The extracellular matrix (ECM) is a network of proteins and carbohydrates that surrounds and supports cells in tissues throughout the body. In this image, the ECM (pink) is present between the axons of nerve cells. Blue-colored nerve cell axons are surrounded by brown-colored, myelin-supplying Schwann cells, which act like insulation to help speed the transmission of electric nerve impulses down the axon. The tiny brown spots within the ECM are collagen fibers.
Image courtesy of Tom Deerinck, NCMIR, UCSD.