Week 1- Vestibular A&P Review Flashcards
PART 1: PERIPHERAL VESTIBULAR SYSTEM - INTRO AND OTOLITH ORGANS
PART 1: PERIPHERAL VESTIBULAR SYSTEM - INTRO AND OTOLITH ORGANS
What are the 3 main roles of the vestibular system?
- Estimates body position and movement.
- Postural control.
- Control eye movements.
What is an additional role of the vestibular system?
-Autonomic function and consciousness.
- What is pitch?
- What is yaw?
- What is roll?
- Pitch = rotation around y-axis (flexion and extension).
- Yaw = Rotation around z-axis (rotation).
- Roll = Rotation around x-axis (side bending).
-Pitch (singer pitches up and down), Yaw (like naw nodding head no)
What structures make up the peripheral vestibular system? (2)
- Vestibular Apparatus (body labyrinth, otolith organs, semi-circular canals)
- CN 8- Vestibular branch
What structures make up the central vestibular system? (4)
- Vestibular Nuclei
- Vestibular Tracts
- Vestibulocerebellum
- Vestibular Cortex
Which system is mainly responsible for relaying information (velocity and acceleration of head)?
Peripheral Vestibular System
What are the (3) primary functions of the peripheral vestibular system?
- Stabilize visual images on the fovea of the retina during head movement allow for clear vision.
- Maintain postural stability, especially during movement of head.
- Provide information for spatial orientation.
In the peripheral vestibular system, the ___________ labyrinth is suspended inside the _______ labyrinth and is protected by perilymphatic fluid and supportive connective tissue.
- membranous
- bony
What are the 3 main parts of the membranous labyrinth?
- Vestibule
- Semicircular Canals
- Cochlea
What are the 2 main otolith organs located in the vestibule?
- Utricle
- Saccule
- ________ detects movement in the horizontal plane.
- ________ detects movement in the vertical plane.
- Utricle
- Saccule
Within the utricle and saccule there are hair cells known as __________ that detect movement and transduce minute displacements into behaviorally relevant potentials.
-Stereocilia
- Movement of stereocilia towards kinocilium = ________.
- Movement of stereocilia away from kinocilium = ________.
- EXCITATORY
- INHIBATORY
- The hair cells (stereocilia) are encased in a gelatinous layer (macula) and on top of the hair cells are calcium carbonate crystals called what?
- What does it do?
- Otoconia
- Helps to transmit tiny movements and make the organs more sensitive to movements since they are heavier than the structures below.
PART 2: PERIPHERAL VESTIBULAR SYSTEM - SEMICIRCULAR CANALS
PART 2: PERIPHERAL VESTIBULAR SYSTEM - SEMICIRCULAR CANALS
What are the (3) semicircular canals?
- Anterior
- Posterior
- Horizontal
Semicircular canals are responsible for relaying information about ________ velocity while the otolith organs are responsible for relaying ________ velocity.
- angular
- linear
- The semicircular canals are encased in the bony labyrinths and contains a fluid called what?
- What does this fluid do?
- Endolymph
- Head rotation causes movement of endolymph, which then causes movement of hair cells.
The ampulla is a bulbous formation at the start or finish of each canal that contains the _______, which houses stereocilia and is sensitive to angular movements only.
-Cupula
- SCC hair displacements TOWARDS utricle = _________ cupular displacement
- SCC hair displacement AWAY FROM utricle = _________ cupular displacement
- Utriculopedal
- Utriculofugal
(pedal forwards)
Utriculopedal cupular displacement is _________ for the horizontal canal and __________ for the anterior/posterior canal.
- Excitatory
- Inhibitory
Utriculofugal cupular displacement is _________ for the anterior/posterior canal and __________ for the horizontal canal.
- Excitatory
- Inhibitory`
How are the 6 canals paired?
- Horizontals paired.
- R ant and L post paired.
- L ant and R post paired.
(when one is excited the other is inhibited)
PART 3: CENTRAL VESTIBULAR SYSTEM
PART 3: CENTRAL VESTIBULAR SYSTEM
What are the 3 vestibular reflexes?
- Vestibulo-Ocular Reflex (VOR)
- Vestibulo-Spinal Reflex (VSR)
- Vestibulo-Collic Reflex (VCR)
- Which reflex stabilizes vision during head motion?
- Which reflex stabilizes body during head motion?
- Which reflex stabilizes neck during head motion?
- VOR
- VSR
- VCR
- The _________ can send down inhibitory drive when we need our eyes to do something outside VOR?
- What is VOR Suppression (VOR Cancellation)?
- Cerebellum
- Ability to follow a moving target with eyes and head moving. (watching a tennis ball)
Describe the connection from vestibular to ocular nuclei.
Labyrinth → vestibular nuclei → ascending tracts (cross at MLF) → ocular motor nuclei (III, IV, VI)
- If we rotate our head to the left what canal is being excited, which is being inhibited?
- If we are compensating with our eye movements what muscles will be excited during L rotation?
- left, right
- L adductor, R abductor
What is the purpose of the vestibulospinal reflex (VSR)?
-Generation of compensatory body movements to maintain head and postural stability.
What are the (5) steps of the VSR?
- Head tilts to side
- Ipsilateral SCC/otolith excitation
- ↑ Input from vestibular nerve vestibular nuclei ipsilaterally
- MVST/LVST descending drive to truncal muscles
- ↑ Lateral truncal extension ipsilaterally/ ↑ truncal flexion contralaterally
What are the (3) cervical reflexes?
- Cervico-Ocular Reflex (COR)
- Cervicospinal Reflex (CSR)
- Cervicocollic Reflex (CCR)
_____ interacts closely with and can supplement VOR under certain circumstances and involves eye movements driven by neck proprioceptors.
-COR
_____ can supplement VSR under certain circumstances and involves changes in limb position driven by neck afferent activity.
-CSR
_____ helps stabilize head on body and involves afferent input caused by changes in neck position (stretch) → contralateral reflexive contraction of appropriate neck muscles.
-CCR
The central vestibular system relies on ________ AND _________ references.
- Internal (vestibular)
- External (visual/somatosensory)
What are the (4) main structures of the central vestibular system?
- Vestibular Nuclei (lateral, medial, superior, inferior)
- Vestibular Tracts (medial/lateral vestibulospinal, vestibulocerebellar)
- Vestibulocerebellum
- Vestibular Cortex
- ________ vestibulospinal tract is involved in head and body position in space, walking upright, and righting/equilibrium reactions.
- ________ vestibulospinal tract is involved in head movements and integrating head and eye movements.
- Both travel to neck ________ musculature.
- Lateral
- Medial
- Extensor
Vestibulocerebellum is responsible for postural and gaze stabilization via modulation of VOR and VSR by doing what?
-Suppressing/Cancellation
- The ______________ tract is important with intended vs actual movement/error correcting mechanism.
- The _________-_________ loop involves adaptation of postural responses based on prior experiences.
- Vestibulocerebellar
- Cerebellar/Cortical loop
