Understanding:
• Hair cells in the semicircular canals detect movement of the head
The vestibular system is a sensory system in the inner ear that is involved in balance and spatial orientation (proprioception)
- Within the semicircular canals are gelatinous caps called cupula, which are embedded with numerous hair cells
- When the head moves, the fluid in the semicircular canals (endolymph) follows the direction of movement (due to inertia)
- This fluid movement exerts pressure on the hair cells embedded in the cupula, triggering nerve impulses
- There are three semicircular canals at 90º angles to one another, allowing head movement to be detected in all three planes
- The brain integrates information from the semicircular canals in each ear in order to identify head position and movement
Detecting Head Movement – Vestibular System