The invention relates to a medical catheter for delivering a functional element (50), particularly an implant or a minimally invasive device, having a pressure-actuated displacement unit (20) acting together with the functional element (50) for delivery. The invention is characterized in that the displacement unit (20) comprises a piston (21) disposed loosely in a catheter line (10) and connected to or connectable to the functional element (50), wherein the piston (21) delimits a pressure line (15) during use, said line being designed between a proximal end of the catheter line (10) and a proximal face of the piston (21), such that the piston (21) can be axially displaced relative to the catheter line at least in segments by a pressure, particularly an overpressure and/or a vacuum, for delivering the functional element (50). The invention further relates to a medical system having such a catheter, and a loader for producing such a catheter.
