Jaw actuated lock arrangements for preventing advancement of a firing member in a surgical end effector unless an unfired cartridge is installed in the end effector

A surgical end effector including a first jaw that is configured to operably support a surgical staple cartridge therein and a second jaw that is movably supported relative to the first jaw between open and closed positions. A firing member is supported for axial movement within the first jaw along a shaft axis between a starting position and an ending position. A firing member lockout system is movable between an unlocked position wherein the firing member lockout system is out of engagement with the firing member and a locked position wherein the firing member lockout system is configured to prevent the firing member from being distally advanced from the starting position unless an unfired staple cartridge comprising a cam assembly that is located in an unfired position is supported within the first jaw. The firing member lockout system is configured to be moved from the unlocked position to the locked position when the second jaw is moved to the closed position.