An insertion device (100), in particular a guide catheter (110) and/or balloon catheter (120), for insertion into an animal and/or human body, wherein at least one catheter segment (10, 20) is provided, in which a hollow space (113, 32) and a fluid chamber (115, 125) are arranged around a central region (34), wherein the hollow space (113, 32) and the fluid chamber (115, 125) are separated by a wall (50) and the wall (50) has at least one wall opening (52a, 52b), which is sealed by a resilient membrane (40a, 40b), and wherein the resilient membrane (40a, 40b) is designed, with a sufficient pressure difference between the fluid chamber (115, 125) and the hollow space (113, 32), to bear against a bearing region (111, 30) in the hollow space (113, 32), said bearing region being arranged opposite the at least one wall opening (52a, 52b).
