Flashcards in Vestibular Anatomy Deck (53)
Signs and Symptoms of Vestibular Dysfunction
Loss of balance & possible falls
Broad-based stance (to accommodate for imbalance)
Sweating, nausea, and vomiting (due to ANS involvement)
What are the two main reflexes of the vestibular system?
VOR: Vestibulo-ocular Reflex
VSR: Vestibulo-spinal Reflex
What are head movements detected by?
Vestibulo Ocular Reflex
Stabilizes eye in space
Necessary to see while head is in motion
Components of VOR:
angular and linear VOR
Helps maintain desired orientation to environment
Cervicoocular Reflex (COR)
Does not play direct role in gaze stability
May help VOR to compensate
Proprioceptors and somatosensory receptors
-C1-C2 dorsal nerve roots
Cervicocollic Reflex (CCR)
Provides head stability
Contraction of stretched muscles to align head
Cervicospinal Reflex (CSR)
acts in conjuction with the VSR
-provides postural stability through limb activation
Three axes of rotation:
Three axes of translation
up and down
head movement side to side in horizontal plane (shaking head no)
lateral side bending
What do semicircular canals detect?
What do otoliths (saccule and utricle) detect?
Functions of peripheral vestibular system:
Stabilization of visual images on the fovea of the retina during head movement to allow clear vision
Maintain postural stability especially during movement of the head
Provide information used for spatial orientation
Peripheral vestibular components:
Semicircular canals (SCC)
CN VIII: Vestibulocochlear nerve
Orientation of semicircular canals:
What are the components of the labyrinth?
3 semicircular canals
What is the bony labyrinth filled with?
perilymphatic fluid (similar to cerebral spinal fluid)
What is the membranous labyrinth?
suspended within the bony section and contains membranous portions of the canals and utricle and saccule
What is the membranous labyrinth filled with?
endolymphatic fluid (similar to intracellular fluid)
contain the cupula (hair cells) which convert displacement into neuro firing thru bending of hair cells
What does ampulla detect?
(Utricle and Saccule): contain calcium carbonate crystals called otoconia
What does otolith organ detect?
gravity and acceleration