A loading unit (200d) configured for engagement with a surgical instrument (100), the loading unit (200d) comprising: a proximal body portion (210) configured to be releasably attached to an elongated portion (120) of said surgical instrument (100)； an end effector (220) disposed in mechanical cooperation with the proximal body portion (210), the end effector (220) including an anvil assembly (300d) and a cartridge assembly (400d), at least one of the anvil assembly (300d) and the cartridge assembly (400d) being movable with respect to the other of the anvil assembly (300d) and the cartridge assembly (400d) between an open position and an approximated position, the anvil assembly (300d) includes a tissue contacting surface (310d), and the second jaw member also includes a tissue contacting surface (410a) and a first imaging device (800d), a second imaging device (802d) and a third imaging device (804d), each imaging device (800d, 802d, 804d) being disposed on the anvil assembly (300d) facing the cartridge assembly (400d).
