Vestibular Anatomy
Descending tract that is ipsilateral through the entire spinal cord
Lateral Vestibulospinal Tract
Tract that has excitatory effect on trunk and limb extensors and inhibitory effect on flexors
Lateral Vestibulospinal Tract
This type of VOR compensates during translation
Linear VOR
3 Major Components of Vestibular System
Peripheral Sensory Apparatus, Central Processing System, Motor Output System
Vestibular Nuclear Complex is located in the ____ & ____ consists of ________
Pons, Medulla, 4 Vestibular Nuclei- Superior, Medial, Lateral, Inferior
The gain of the VOR is ______________ and is regulated in part by the _________.
Ratio of head to compensatory eye movement, Cerebellar Flocculus
If you have 2 targets and you look at 1 then the other this is an example of
VOR cancellation
Turning the head back and forth while maintaining your gaze on a stable object is an example of
VOR x1
Moving an object opposite the direction that you are turning your head is an example of
VOR x2
Output of the central vestibular system (through the vestibular nuclei) travel to the ocular muscles serving the ____ reflex and to the spinal cord serving the ____ reflex
VOR, VSR
The primary function of the semicircular canals is to sense _______ acceleration of the head and are most sensitive to ______ frequency motion with an example being _____.
Angular, Higher Frequency, Gait
Posterior canal shares the same plane as the contralateral _________ canal
Anterior
Hair cells in the ampula send its signal to the _______ cells in the internal auditory meatus, here the vestibular ganglion sends neurons to the __________ and the _________ lobe of the Cerebellum
Bipolar, Vestibular Nuclei in the brainstem, Flocculonodular
Peripheral Sensory Apparatus contains....
Bony Labyrinth (located within the temporal bone), Membranous Labyrinth, and specialized hair cells
Major processor for unconscious proprioception
Cerebellum, esp. middle or vermis
This type of reflex can be used to help substitute for VOR in patients with bilateral vestibular loss to increase gaze stabilization
Cervico-ocular reflex
Vestibular Nuclei recieve input from the _______ Vestibular Nerve, ________ Vestibular Nuclear Complex, Cerebellum, Brainstem reticular activating system, Spinal Cord
Ipsilateral, Contralateral
Head tilt to the right will stimulate both the otoliths and semicircular canals. The stimulation of the otolith results in transmission of impulses to the S.C. via the _______.
LVST
Lateral nucleus is the origin for the _________ vestibulospinal tract and is also known as _______ nucleus
LVST, Deiters
Spinal Anterior Horn cell activity is influenced by information from the semicircular canals and the otoliths through 3 major pathways
LVST, MVST, RST
Bony Labyrinth contains....
3 Semicircular Canals and the vestibule
Crista receptors are sensitive to _______ acceleration such as turning your head
Angular
This type of VOR compensates for rotation and is primarily responsible for gaze stabilization
Angular VOR
RST recieves input from the _______ and acts to mediate ______________.
4 Vestibular nuclei, Postural Adjustments
Membranous Labyrinth contains...
5 sensory organs of the Peripheral Vestibular System
Primary roles of the Cerebellum in the vestibular system
Adaptive Processor, Monitors Vestibular Performance
The ______ is the enlarged area at the end of the canals which contains _____. Hair cells are found within the ______.
Ampula, Crista, Crista
Endolymph that does not drain into the venous sinuses causes too much fluid to build up and results in swelling of the ________ and ___________. This can cause dysfunction of the ________ & _______system because hair cells are firing even when there is no stimulation.
Cochlear Duct, Saccule, Auditory, Vestibular
Receptor in the semicircular canal is known as the _____
Crista
Gelatinous membrane called the ______ overlies each set of hair cells in hte ________. Calcium Carbonate crystals called _______ are located in the gelatinous membrane of the _______.
Cupula, Semicircular Canals, Otoconia, Otolith
When you turn your head to the right, hair cells in the maccula causes the horizontal canal on the right to ___________ and _______ on the left.
Depolarize, Hyperpolarize
Peripheral Sensory Apparatus is responsible for what 2 things
Detecting and relaying info about Head Angular and Linear Velocity to the Central Processing System, Orientation of the head with respect to gravity
A flu or cold increases the pressure in the _______________ tube which may cause a person to feel dizzy
Eustachian Tube
Central Processing System works with what 3 sensory inputs to provide info about the position and movement of the head in space
Input from the Peripheral Sensory Apparatus, Somatosensory, and Visual system
During head movements, posture, & Gait, what action do Motor Outputs generate?
Generate Compensatory Eye Movements (for gaze stability) & Compensatory Body Movements (for postural stability)
Head movement to the left causes an _______ in the firing rate of the left CN VIII, and an ______ in the firing rate of the right CN VIII
Increase, Decrease
Peripheral Sensory Apparatus is located in the _____, the Central processing system is located in the _______, and the Motor Output System is mediated through the ______ & ______ reflex.
Inner Ear, Vestibular nuclear complex in the brain stem and cerebellum, VOR & VSR
Otolith detects _______ acceleration of the head. More specifically, the utricle detects _______ and the saccule detects _______. The Otolith is most sensitive to ____ frequency motion with an example being ________.
Linear, Horizontal Plane Linear Acceleration, Vertical Linear Acceleration in the Sagittal plane, Lower Frequency, Standing in place
Macula is the receptor for _______ acceleration, contain calcium carbonate crystals called ________
Linear, Otoconia
what is the sensory organ of the utricle and saccule
Macula
Role of the VSR during head movements, locomotion and posture
Maintain whole body equilibrium by facilitating and inhibiting skeletal extensor muscle activity
This tract descends bilaterally and terminates in the cervical and thoracic region and has exitatory and inhibitory effects on neck musculature
Medial Vestibulospinal Tract
This tract is associated with vestibullocollic reflex which is a series of responses that stabilize the head in space
Medial Vestibulospinal Tract
A disorder of endolymphatic drainage resulting in unilateral hearing loss, horizontal nystagmus, tinnitus
Menieres
A lesion to the ________ part of the cerebellum will primarily affect the VSR and will result in what?
Middle (Vermis), Postural and Gait Instability
The duration of VOR response and Otolith input is adjusted and processed in the _______
Nodules-Cerebellum
The Membranous Labyrinth consists of 2 swellings. What are they
Otolith (Utricle and the Saccule) and 3 semicircular canals
LVST linds directly with alpha and gamma motoneurons of the anterior horn cell and controll _____________
Otolith Mediated Postural Responses
A head tilt to the right will result in an increase in extensor activity on the _____ and an increase in flexor activity on the ______ via the LVST to stabilize the head and body.
Right, Left
30 degrees of head rotation to the left is accompanied by 30 degrees lateral eye movements to the ____ due to activation of the left ______ and the right ______, this is due to the gain of the VOR with the ratio of head to eye movement being close to ___.
Right, Left Medial Rectus, Right Lateral Rectus, 1
Which otolithic organ responds to acceleration within the saggital plane like riding an elevator
Saccule
Hair cells are located in the.....
Saccule, Utricle, and cristae of Semicircular canals
With head movement you have afferent input from the _________ ascend to the _______ and is primarily responsible for producing compensatory eye movements
Semicircular Canals, Vestibular Nuclei
Each hair cell contains many _________ and 1 ________
Stereocilia, Kilocilium
Which otolithic organ responds to balance and righting reactions with position of the body
Utricle
Because the utricle and saccule are sensitive to gravity or linear acceleration, bending your head foward will stimulate the _______ while bending your head to the side will stimulate the ________
Utricle, Saccule
Afferent signals from the Labyrinths travel via CN VIII to the _______ & _________
Vestibular Nuclear Complex, Flocculonodular Lobe of the Cerebellum
Efferent input from the ________ travel to the _____________, and then to the output neurons of the VOR which are CN ___,____,& ____ controlling eye movement
Vestibular Nuclear Complex, Ocular motor nuclei, CN III,IV&VI
Efferent signals from the __________ go to the _________, Cerebellum, Brainstem reticular activating systems, parietal cortex, ________ Vestibulospinal tract, and __________ Vestibular Nuclear Complex
Vestibular Nuclear Complex, Oculomotor Nuclei, Ipsilateral, Contralateral
Central Processors of the Vestibular System
Vestibular Nuclei, Cerebellum
Each ___________ maintains a baseline firing rate that is symetrical at rest, with head movement a change in firing rate will occur in ______ directions
Vestibular Nuclei, Opposite
VSR reflexes
Vestibulocollic, Labyrinthin reflexes
MVST has an __________ effect on most neurons
inhibitory
A head turn to the right will cause displacement of the hair cells in the ampula to the _____
left
Spinning to the right can elicit nystagmus, which will begin with VOR pattern or slow movement to the ______ followed by a compensatory rapid eye movement to the ______ (VOR with corrective saccade)
left, right
Primary function of the VOR
maintain faze stability during head motion
Pathway for modulating tone and postural control
reticular spinal tract
Components of the peripheral sensory apparatus
semicircular canals, otolith, CN VIII
