Term
| vestibular system consist of: |
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Definition
1: membranous labyrinth and sensory housed in a bony labyrinth
2: Cranial nerve VIII and it's cell bodies (scarpa's ganglia)
3: vestibular nuclei( on the floor of the 4th ventricle)
4: ascending and descending tracts |
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Term
| 3 roles of the vestibular system |
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Definition
1: eye position-
during movements to stabilize image on the retina
2: Appendicular and axial muscle tone
for control of postural support and balance (vestibulo-spinal reflex)
3: Kinesthesia/proprioception
provide concious awareness of spatial orientation |
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Term
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Definition
a series of tubes made of fine membranes that contain the peripheral sensory receptors of the the vestibular system
(hair cells) |
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Term
| The membranous labyrinth contains a fluid called_______ |
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Definition
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Term
| the membranous labyrinth is separated from the bone cavity by ___________ |
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Definition
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Term
receptors of the vestibular apparatus are located within specific sites within the membranous labrinth.
A total of 5 sites on each side of the body |
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Definition
3 in the semicircular canals
2 in the vestibule (saccule and utricle) |
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Term
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Definition
3 canals arranged at right angles to each other.
together they perform the dynamic function of detecting angular velocity of the head in all planes. |
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Term
Horizontal canal
horizontal when?
Activated when? |
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Definition
Head is flexed forward to 30 degrees
Activated with rotation around the body axis |
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Term
Anterior and Posterior canals
activated when?
work how? |
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Definition
Activated with rotation in frontal and sagittal planes
Work together on opposite sides of body |
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Term
| Semicircular canals are especially important for _________ |
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Definition
| stabilizing the eyes during head movement |
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Term
| Cristae are innervated by ________ |
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Definition
| peripheral vestibular nerve fibers |
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Term
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Definition
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Term
| Hair cells in the otolithic organs protrude upwards into the __________ |
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Definition
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Term
| movement of cupula and hair cells is caused by _________ |
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Definition
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Term
| Mechanical deflection of hair cells either _________ or _________ the vestibular nerve. |
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Definition
depolarize
or
hyperpolarize |
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Term
| __________ of hair cell bend effects polarization |
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Definition
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Term
| Steriocilium toward kinocilum causes __________ of vestibular nerve |
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Definition
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Term
| Stereocilium away from kinocilium ___________ the vestibular nerve |
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Definition
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Term
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Definition
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Term
| an increase or decrease in the firing of the tonically active nerve signals the ____________ of rotation |
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Definition
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Term
Rotation around the body axis to the left causes:
left horizontal canal to _________
right horizontal canal to _________ |
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Definition
Left: depolarize
Right: hyperpolarize |
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Term
| Receptors in the semicircular canals are ________ adapting |
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Definition
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Term
| Why are semicircular canals rapidly adapting? |
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Definition
| Because the cupula has a spring=like action that restores it to its resting position |
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Term
| The semicircular canals have a low threshold, therefore? |
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Definition
| they are highly sensitive receptors and respond to very small angular changes |
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Term
| Semicircular receptors responses are _______ |
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Definition
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Term
| Since semicircular cells responses are graded, an increase in velocity, increases _________ |
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Definition
| the number of hair cells that are activated |
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Term
| The Otolithic organs are located: |
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Definition
| between semicrcular canals + chochlear duct |
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Term
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Definition
2 large chambers
Utricle
Saccule |
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Term
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Definition
Linear acceleration and deceleration of the head
Static position of the head in gravity |
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Term
| the job of the Otolithic organs are to: |
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Definition
maintain the head upright in space
modulate postural muscle tone relative to the position of the head |
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Term
| Both ends of the _____________ are continuous with the utricle. |
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Definition
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Term
| The utricle and saccule are filled with _________ |
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Definition
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Term
| Endolymph is produced in the _____________ |
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Definition
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Term
| Endolymph is drained by the ____________ into the _____________ of the ___________ |
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Definition
| Endophymph is drained by the endolymphatic duct into the venous sinuses of the dura mater |
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Term
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Definition
| The sensory organ on the wall of the utricle and saccule |
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Term
| Macula is covered with __________ and embedded with ___________ |
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Definition
| Macula is covered with A GELATINOUS LAYER and embedded with CRYSTALS OF CALCIUM CARBONATE- OTOLITHS (OTOCONIA). |
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Term
| Otoliths(ottoconia) do what? |
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Definition
| give more mass to the gelatinous, giving it more inertia |
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Term
When the head is positioned upright, the macula in the:
utricle is in the _____________
saccule is in the _____________ |
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Definition
When the head is positioned upright, the macula in the:
utricle is in the HORIZONTAL PLANE
saccule is in the VERTICAL PLANE |
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Term
| Macula receptors are _________ adapting |
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Definition
| Macula receptors are NON adapting |
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Term
| Macula receptors are non adapting because? |
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Definition
| Utricle and Saccule are sensitive to static head tilt in multiple planes, therefore must always be active, and non adapting |
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Term
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Definition
benign Paroxysmal positional vertigo
when utricle otoconia break loose and float into semicircular canals (usually posterior canal) |
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Term
| the vestibular portion of the 8th cranial nerve is a _________ nerve |
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Definition
| the vestibular portion of the 8th cranial nerve is a BIPOLAR nerve |
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Term
| the cell bodies of the Vestibular nerve forms _____________ |
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Definition
| the cell bodies of the Vestibular nerve forms SCARPA'S GANGLIA |
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Term
| After the vestibular nerve leaves scarpa's ganglia it join's with _____________ |
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Definition
| After the vestibular nerve leaves scarpa's ganglia it join's with COCHLEAR NERVE FIBERS. |
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Term
| After the vestibular nerve joins with the cochlear nerve it travels into the ______________ |
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Definition
| After the vestibular nerve joins with the cochlear nerve it travels into the INTERNAL AUDITORY CANAL |
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Term
| After the vestibular nerve joins with the ________ it travels into the _____________ with the ____________ |
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Definition
| After the vestibular nerve joins with the COCHLEAR NERVE it travels into the INTERNAL AUDITORY CANAL with the FACIAL NERVE |
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Term
| After the vestibular nerve travels in the internal auditory canal with the facial nerve it passes through the ___________ and opens into the __________ |
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Definition
| After the vestibular nerve travels in the internal auditory canal with the facial nerve it passes through the TEMPORAL BONE and opens into the POSTERIOR FOSSA |
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Term
| the vestibular nerve enters the brainstem at the ________________ |
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Definition
| the vestibular nerve enters the brainstem at the pontomedullary junction |
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Term
| Primary vestibular afferents synapse on _____________ in the ____________ of the ___________ and in the ___________ |
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Definition
| Primary vestibular afferents synapse on SECOND ORDER NEURONS in the VESTIBULAR NUCLEI of the BRAINSTEM and in the CEREBELLUM |
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Term
| The vestibular nuclei form a ____________ shaped complex located in ______ sides of the _________ in the floor of the _____________ |
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Definition
| The vestibular nuclei form a DIAMOND shaped complex located in BOTH sides of the BRAINSTEM in the floor of the 4TH VENTRICLE |
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Term
| the vestibular nuclei is surrounded by what laterally? |
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Definition
| inferior cerbellar peduncle |
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Term
| the vestibular nuclei is surrounded by what medially? |
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Definition
| pontine reticular formation |
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Term
| the vestibular nuclei is surrounded by what rostrally? |
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Definition
| middle cerebellar peduncle |
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Term
| the vestibular nuclei is surrounded by what ventrally? |
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Definition
| Trigeminal nerve nucleus and spinal tract |
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Term
| the 4 main divisions of the vestibular nuclei |
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Definition
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Term
| adjacent to the MVN is the ____________ which shares in maintaining ___________ in the ____________ |
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Definition
| adjacent to the MVN is the NUCLEUS PERPOSITUS HYPOGLOSSI which shares in maintaining GAZE POSITION in the HORIZONTAL PLANE |
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Term
| in the rostral midbrain the ______________ contributes to gaze holding in the ____________ |
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Definition
| in the rostral midbrain the INTERSTITIAL NUCLEUS OF CAJAL contributes to gaze holding in the VERTICAL PLANE |
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Term
| Areas that support the vestibular nuclei in the task of controlling eye movements are: |
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Definition
NUCLEUS PREPOSITUS HYPOGLOSSI
INTERSTITIAL NUCLEUS OF CAJAL |
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Term
| Each nucleus recieves input from both the ______________ and the ___________ except for the ___________ which receives the majority of it's vestibular input from the _________ |
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Definition
| Each nucleus receives input from both the SEMICIRCULAR CANALS and the OTOLITHS except for the LVN which receives the majority of it's vestibular input from the UTRICLE |
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Term
Fibers from: _(1)_, _(2)_, _(3)_, _(4)_, _(5)_
terminate in all 4 vestibular nuclei |
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Definition
Cerbellar flocculaus
nodulus
fastigial nucleus
vermis
uvula |
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Term
afferents to the vestibular nuclui from the ____, _____, and ______ are relayed through the cerebellum and help modulate
_(1)_ reflex, _(2)_ reflex, and _(3)_ reflex |
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Definition
afferents to the vestibular nuclui from the EYES, NECK, and LIMBS are relayed through the cerebellum and help modulate:
VESTIBULO-OCULAR reflex, VESTIBULOCOLLIC reflex, and VESTIBULOSPINAL reflex |
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Term
| Ascending projections to the __________ in the ____ and ______ via the _________________ and runs in the floor of the _____________ |
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Definition
| Ascending projections to the OCULAR MOTOR NUCLEI in the PONS and MIDBRAIN via the MLF (MEDIAL LONGITUDINAL FASCICULUS) and runs in the floor of the 4TH VENTRICLE |
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Term
projections descend in:
_(1)_, _(2)_ ipsilaterally, and _(3)_ contralaterally |
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Definition
projections descend in:
MLF, LVST (LATERAL VESTIBULO SPINAL TRACT) ipsilaterally, and MVST (MEDIAL VESTIBULO SPINAL TRACT) contralaterally |
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Term
vestibular nuclei sends extensive input to:
_(1)_, _(2)_, _(3)_, _(4)_ |
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Definition
vestibular nuclei sends extensive input to:
FASTIGAL NUCLEI, FLOCCULONODULAR LOBE, UVULA CEREBELLUM, VERMIC |
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Term
| Function of the ascending VTC? |
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Definition
| involves the vestibular system and perception of self in space |
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Term
| Ascending VTC travels in the __________ adjacent to _(1)_ and the _(2)_ |
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Definition
| Ascending VTC travels in the RETICULAR FORMATION adjacent to MLF and the LATERAL LEMNISCUS |
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Term
| Secondary fibers of the Ascending VTC travel from the ____ and the ____ and terminate in the ____________ near the ____________ |
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Definition
| Secondary fibers of the Ascending VTC travel from the LVN and the SVN and terminate in the CHIEF (MAIN SENSORY NUCLEUS OF THE THALAMUS near the MEDIAL GENICULATE NUCLEUS |
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Term
| Thalamocortical projections to areas of _______ of the ___________ produce subjective _________ of _______ and ____________ |
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Definition
| Thalamocortical projections to areas of ASSOCIOATION of the PARIETAL LOBE produce subjective SENSATION of ROTATION and BODY DISPLACEMENT |
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Term
| The peripheral vestibular endorgan is supplies by the _______________ which often is a branch of the ____________ but occasionally branches directly off the _____________ |
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Definition
| The peripheral vestibular endorgan is supplies by the LABRYINTHINE ARTERY which often is a branch of the AICA (ANT-INF CEREBELLAR ARTERY) but occasionally branches directly off the BASILAR ARTERY |
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Term
| The labyrinthine artery has no _________ _______ and is highly susceptible to _________, which results in _______ ______ and sudden onset of ________ |
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Definition
| The labyrinthine artery has no ANASTOMOTIC NETWORK and is highly susceptible to ISCHEMIA, which results in HEARING LOSS and sudden onset of VERTIGO |
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Term
| The area of the brain containing the vestibular nuclei is supplied by the ______ (inferior aspects) and the ______ (superior aspects) |
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Definition
| The area of the brain containing the vestibular nuclei is supplied by the PICA (inferior aspects) and the AICA (superior aspects) |
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Term
| the purpose of the VOR (vestibulo-ocular reflex) is to maintain _______ ______ during ________ motion |
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Definition
| the purpose of the VOR (vestibulo-ocular reflex) is to maintain STABLE VISION during HEAD motion |
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Term
| With VOR, when the head is turned to the left, the left vestibular nerve _______ firing and the right ________ firing |
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Definition
| With VOR, when the head is turned to the left, the left vestibular nerve INCREASES firing and the right DECREASES firing |
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Term
| Changes in firing rates with VOR influence discharge from the ______, then sends signals via the ______ to activate the _____ _____ _____ and ____ _____ _____ |
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Definition
| Changes in firing rates with VOR influence discharge from the MVN, then sends signals via the MLF to activate the RIGHT ABDUCENS NUCLEUS and LEFT OCULOMOTOR NUCLEUS |
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Term
| With VOR, if the head is turned to the left, inhibitory impulses are sent to nuclei that control the ________ muscles and result in a _________ _______ eye movement towards the _______ called ___________ |
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Definition
| With VOR, If head is turned to the left, inhibitory impulses are sent to nuclei that control the ANTAGONISTIC muscles and result in a LATERAL COMPESNATORY eye movement towards the RIGHT called NYSTAGMUS |
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Term
| Nystagmus is characterized by a ____ phase _____ from midline and a _____ phase as the eyes rebound towards the midline |
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Definition
| Nystagmus is characterized by a SLOW phase AWAY from midline and a FAST phase as the eyes rebound towards the midline |
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Term
| The direction of the nystagmus is named by the ________ of the ______ |
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Definition
| The direction of the nystagmus is named by the DIRECTION of the FAST PHASE |
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Term
| eye movements are ________ to the plane of the canal that has been stimulated |
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Definition
| eye movements are PARALLEL to the plane of the canal that has been stimulated |
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Term
| Nystagmus is a normal response to ______ ____ ______ |
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Definition
| Nystagmus is a normal response to ROTARY HEAD VELOCITY |
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Term
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Definition
semicircular canals
cerbellum
contraleteral vestibular nuclei |
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Term
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Definition
MLF to oculomotor nuclei
cerbellum
dorsal pontine RF
adjacent RF
thalamus |
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Term
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Definition
maintain eye position during head movement
arousal
conscious awareness of spatial orientation |
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Term
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Definition
cerbellum
utricle and saccule
semicircular canals (minimal) |
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Term
LVN
(deiter's)
Major output |
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Definition
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Term
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Definition
facilitates antigravity limb tone through vestibulospinalreflexes
spacial orientation |
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Term
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Definition
Semicircular canals (1* horizontal)
utricle + saccule
Cerbellum
Contralateral vestibular nuclei
reticular formation |
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Term
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Definition
Ipsilateral vestibulo spinal tract
MLF to oculomotor nuclei
cerbellum
adjacent RF |
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Term
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Definition
coordination of eye, head and neck movements
gaze holding in horizontal plane
head control and stability- head
turning and righting |
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Term
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Definition
utricle +saccule
cerebellum |
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Term
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Definition
Cerbellum
RF
Contralateral vestibular nuclei |
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Term
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Definition
| integrates vestibular signals from 2 sides with signals from cerebellum and RF |
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Term
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Definition
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Term
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Definition
RF
contralteral vestibular nuclei |
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Term
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Definition
| integrates vestibular signals from 2 sides with signals from cerebellum and RF |
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