What part of the ear contains the apparatus that detects changes in angular movement?

The part of the ear that contains the apparatus for detecting changes in angular movement is the vestibular system, specifically the semicircular canals. These three fluid-filled structures are oriented at right angles to each other and are responsible for sensing rotational movements of the head. When the head moves, the fluid within the canals shifts, stimulating hair cells that send signals to the brain about the direction and speed of the rotation. This information is crucial for maintaining balance and spatial orientation.