Membranes are provided to be specially developed for use in chambers for artificial circulatory assistance which may be employed primarily in cardiovascular procedures, notably to produce arterial capacitance, to regulate blood pressure, to produce aortic counterpulsation and to pump blood. The membrane may have circular sections that may vary in size or not depending on the function to be performed and are interconnected so that the transition between one section and the other is smooth, regardless of the size of each section. Further, chambers and pumps may be used for cardiopulmonary bypass and a pumping system.
