An occluder for occluding a passage in a body, especially in a left atrial appendage (LAA), comprises elongate members having a first end and a second end, the ends being held in or attached to holders, wherein the elongate members extend independently from each other between the holders and wherein the elongate members are collectively enveloped by at least one jacket. The jacket restricts a bending motion of the elongate members when their first ends are approximated to their second ends by moving the two holders relatively to each other. The occluder uses an expanding structure which can be easily handled whereby the movement of the elongate members is restricted by at the jackets which envelop the elongate members. At least the elongate members can be made of bioresorbable material.
