Examines the expression, structure and function of the four major classes of ECM macromolecules: collagen, proteoglycans, non-collagenous structural proteins and glycoproteins. In addition to forming elaborate networks that give tissues and organs their unique architectural design and biomechanical properties, ECM molecules act as potent regulators of all cellular activities. Emphasis is placed on the morphoregulatory contribution(s) of ECM molecules to normal and pathological development.