Vestibular function Flashcards
What is vestibular function?
The control of posture and balance
Where are the vestibular organs found?
In the inner ear, embedded in the temporal bone
What are the otolith organs?
Utricle
Saccule
What are the ampulla and what do they contain?
Swellings at the bases of the semi-circular canals
They contain sensory hair cells which are embedded in a flexible gelatinous structure and are distorted by movement of the endolymph
What does the utricle measure?
Back/front tilt and horizontal acceleration
What does the saccule measure?
Vertical acceleration
What do the semi-circular canals measure?
Rotational acceleration
What are the kinocilium and sternocilium?
Types of hair cell cilia
What does distortion of cilia towards the kinocilium result in?
An increase in action potentials in the vestibular nerve
What does distortion of cilia away from the kinocilium result in?
A decrease in action potentials in the vestibular nerve
What is the kinocilium?
A single large hair cell cilia
What is the maculae?
Sensory apparatus of the utricle and saccule
Describe the structure of the maculae.
Contains cilia which protrude into a gelatinous membrane called the otolith membrane CaCO3 crystals (otoliths) are embedded in the otolith membrane
What do tonic labyrinthine reflexes do?
Keep the axis of the head in a constant relationship with the rest of the body
What do dynamic righting reflexes do?
Rapid postural adjustment
Stops you falling when you trip
