Simulator for medical training having at least a detachable, fluid-tight hollow member comprising: at least a portion (1; 25) made of a self-sealing material; an opening (2; 17) to fill said hollow member with a fluid, said opening (2, 17) being provided with closure means (4; 26) or being connected (8) to closure means; fastening means (4,5; 28) to detachably fasten said hollow member to said simulator. The portion made of self-sealing material allows multiple punctures before having to be replaced.