What is the makeup of the matrix in connective tissue?
There are three main types of extracellular matrix (ECM): loose connective tissue (Tendons, dermis, etc.), dense connective tissue (cartilage, bone) and basement membranes (underlie any epithelia and form special structure like molecular filter of the glomeruli). Each type of ECM is made of many types of glycoproteins but each is primarily made of examples of three types of proteins that are specific for each kind of connective tissue: 1) collagens for the fibrous foundation of all types of connective tissue. 2) proteoglycans (small proteins with lots of carbohydrate attached to them) that bind to lots of water and growth factors and swell to fill much of the space occupied by connective tissue. For example, proteoclycan is responsible for the squishy cusioning properties of cartilage. 3) multi-adhesive proteins like laminin and fibronectin, which tie things together by being able to bind to collagens, proteoglycans and to cells.
