What Do All the Different Hinged Surfaces on the Airliner's Wing Do?

There are lots of moving parts to a wing besides the trailing edge flaps and leading edge slats. Ailerons are hinged rectangular parts on the aft outer portion of the wing that enable the aircraft to bank, or turn; as one aileron goes up on one wing, another simultaneously moves down on the other. Spoilers on top of the wing also play a role in the banking of an airplane but, most importantly, they reduce lift, acting as speed brakes to help slow down the aircraft or quicken the descent.