PHYSIOLOGY OF EQUILIBRIUM

1. The brain receives sensory information from three sources:

• Vestibular part of the inner ear, which is stimulated by head movements i.e. it is responsible for maintenance of equilibrium during head movements:
1. The three semi-circular canals are stimulated by angular head movements i.e. rotation.
2. The otolith organs (utricle and saccule) are stimulated by linear head movements - i.e. movement in a straight line.
• Vision.
• Proprioceptors of the muscles, joints, and tendons.

• The brain integrates these sensory information.
• The brain sends motor orders to two groups of muscles:

1. The extra-ocular muscles to keep the eyes stable.
2. The spinal muscles to keep the limbs and trunk stable.

Category: Physiology Notes