Unstriated (smooth) musculature includes contractile tissue of many hollow organs, blood vessels, lymphatic vessels and other structures in the human body. It differs from striated muscles, in that it is not subject to voluntary control. Actin, myosin and intermediary filaments of the desmin group (desmin, vimentin) are its predominant filaments. Smooth muscle cells are capable of synthetising collagen and other components of the extracellular matrix, such as proteoglykanes, elastin and laminin, and are probably involved in electromechanical coupling.