Final answer:
The ion channels opened and closed by the movements of stereocilia in the inner ear are known as mechanosensitive ion channels, which respond to mechanical stimuli.
Step-by-step explanation:
Ion channels can be gated and categorized based on how they open and close. The example provided, where the movements of stereocilia on the hair cells of the inner ear respond to sound or motions of the head to open and close cation channels, falls under the category of mechanosensitive ion channels.
These channels are unique as they respond to mechanical deformation or movement, as opposed to chemical or electrical signals.