PHED-2506EL Lecture Notes - Lecture 20: Semicircular Canals, Vestibular Nerve, Dynamic Equilibrium
25 Jun 2018
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Explain how balance is perceived.
Vestibular apparatus – equilibrium receptors in the semicircular canals and vestibule
Maintains our orientation and balance in space
Vestibular receptors monitor static equilibrium
Semicircular canal receptors monitor dynamic equilibrium
Utricular hairs respond to horizontal movement
Saccular hairs respond to vertical movement
•Otolithic movement in the direction of the kinocilia: Depolarizes vestibular nerve fibers
Increases the number of action potentials generated
•Movement in the opposite direction of the kinocilia:Hyperpolarizes vestibular nerve fibers
Reduces the rate of impulse propagation
•From this information, the brain is informed of the changing position of the head
Cristae respond to changes in velocity of rotatory movements of the head
Directional bending of hair cells in the cristae causes: Depolarizations, and rapid
impulses reach the brain at a faster rate
Hyperpolarizations, and fewer impulses reach the brain
The result is that the brain is informed of rotational movements of the head
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Document Summary
Vestibular apparatus equilibrium receptors in the semicircular canals and vestibule. Maintains our orientation and balance in space. Saccular hairs respond to vertical movement: otolithic movement in the direction of the kinocilia: depolarizes vestibular nerve fibers. Increases the number of action potentials generated: movement in the opposite direction of the kinocilia:hyperpolarizes vestibular nerve fibers. Reduces the rate of impulse propagation: from this information, the brain is informed of the changing position of the head. Cristae respond to changes in velocity of rotatory movements of the head. Directional bending of hair cells in the cristae causes: depolarizations, and rapid impulses reach the brain at a faster rate. Hyperpolarizations, and fewer impulses reach the brain.
