Vestibular Function Flashcards
What are the swellings known as at the base of the semi-circular canals ?
Ampulla
What are the sensory organs known as in the Utricle and Saccule ?
Macula
What do the Macula and Ampulla contain ?
Sensory hair cells
What is found in the Ampulla ?
The cupola which spans the width of the ampulla and has the sensory hair cells within it.
What are the two types of hair cells ?
Kinocilium and Steriocilia
What happens if the Steriocilia move towards the Kinoclium ?
The number of AP’s sent along the nerve increases and this causes depolarisation.
What is found in the Macula ?
The Otolith Crystals are embedded in the Otolith Membrane.
What does backwards tilting of the head result in ?
The Otoliths move the Otolith membrane which causes the Steriocilia to move towards the Kinocilium and cause discharge.
Definition of Kinaesthesia
Awareness of the position and movement of the parts of the body by means of sensory organs (proprioceptors) in the muscles and joints.
Which two tracts are involved in the Vestibular system reflexes ?
Vestibulospinal and Vestibulocortical
What do Tonic Labyrinthine reflexes do ?
They keep the head and neck in a constant relationship/axis with the rest of the body.
What do Dynamic Righting reflexes do ?
They rapidly change/correct posture and stop you from falling when you trip.
What do Vestibulo-Occular reflexes do ?
Combine information from the eyes and vestibular apparatus to help with postural control. The vestibular apparatus can affect eye movement.
How does the Vestibular system affect eye movement ?
- Intortion and extortion of the eyes as you move/tilt the head
- Nystagmus when your eyes move against the direction of rotation. You get right nystagmus when rotating to the RHS.
Which Semi-Circular canal is tested via the hot and cold water test ?
Horizontal canal
