What do the semicircular canals in the vestibular system respond to?

The semicircular canals are specialized structures within the vestibular system of the inner ear that play a crucial role in maintaining balance and spatial orientation. They are specifically designed to detect angular acceleration and deceleration, which refers to changes in the speed of rotation of the head.

When the head moves in a circular motion, the fluid within the semicircular canals shifts, stimulating sensory hair cells that are lined along the canals. This mechanical movement translates into nerve impulses sent to the brain, allowing for the perception of rotational movements. Thus, the correct answer highlights the primary function of the semicircular canals, which is to respond to angular changes rather than other types of stimuli.

The other options focus on different physical phenomena: changes in temperature are unrelated to the vestibular function, linear acceleration pertains to straight-line movement and is primarily detected by the otolith organs, and changes in sound frequency relate to auditory processing rather than balance and orientation.