What are those things? Are they used for controlling the movement of the aircraft? Source: Airliners.net (modified to indicate the segments of the vertical stab).
The part I have outlined below is the rudder. That is the only control surface on the vertical stabilizer.
The segments on the leading edge are just the leading edge surfaces. One may include an antenna, but they are only segmented for easier manufacturing and assembly.
The ones just forward of the rudder are panels that cover the rudder attachment and actuating systems. They can be removed for inspection or maintenance purposes.
The rest of the surface, in the middle, is the main structure of the vertical stabilizer. There is a spar on the forward and aft sides, and ribs that run between them. This is all covered by one piece of skin. This creates a structure that is both strong and light weight.
Below is a cutaway showing the internal structure.