A surgical instrument comprising a surgical instrument with opposing jaw members for clamping tissue therebetween. The surgical instrument may comprise a latch at a distal end of the end effector. The latch latches the distal end of the first jaw member to the distal end of the second jaw when the jaw members are in the closed position. Also, one of the jaw members may comprise a moveable tissue-contacting portion and a thermally-controlled spring adjacent to the tissue-contacting portion. The thermally-controlled spring is transitionable between a contracted state and an expanded state. The thermally-controlled spring may comprise a temperature-dependent, two-way memory effect, shape memory material. In the expanded state, the thermally-controlled spring urges the moveable tissue-contacting portion in a direction toward the other jaw member when the jaw members are in the closed position.
