The invention relates to a tissue graft structure for reconstructing a human or animal organ. The tissue graft structure (5) comprises (a) a membrane composite (1), comprising at least one first biologically compatible membrane (2) containing collagen and a second biologically compatible membrane (3) containing collagen, wherein the first membrane (2) and the second membrane (3) are adjacent to each other at the flat sides thereof, and wherein the first membrane (2) is of equine or bovine origin and the second membrane (3) is of animal or human origin and the second membrane (3) is of different origin than the first membrane (2)； and (b) one or more layers (4) of mucosal tissue cells on one or both outer flat sides of the membrane composite (1).
