vestibular system 1 and 2

Question 0

Hair cell neurotransmitter

Answer 0

Glutamate and aspartate

These are excitatory

Question 1

Kinocilium

Answer 1

Long cilia of hair cells, function as strain gauges that transducer mechanical stimuli.

Question 2

Depolarization and hyperpol of hair cells

Answer 2

Cells depolarize when steriocilia bend toward the kinocilia, and hyperpol when they bend away.

Question 3

Static labyrinth

Answer 3

Comprised of the saccule and the utricle

Provides information via vestibular afferents about head position and linear acceleration.

Question 4

Macula of static labyrinth

Answer 4

Mac of the utricle are horizontally oriented and so the steriocilia project vertically from it.
Mac of saccule are vertically oriented and thus steriocilia project horizontally from it.
Detect static position of the head relative to gravity and linear acceleration.

Question 5

Otolithic membrane

Answer 5

Membrane steriocilia and kinocilia are embedded in

Mass of oto creates pull on the steriocilia in the direction of gravity

Question 6

Macula utricle

Answer 6

Kinocilia are oriented toward the srtiola

Question 7

Macula sacculi

Answer 7

Kinocilia are oriented away from the striola.

Question 8

Kinetic labyrinth

Answer 8

Mede by the semicircular canals

Question 9

Crista

Answer 9

Saddle shaped ridges that contain hair cells
Found in the ampulla
Movement of endolymph relative to cristae allows detection of angular acceleration and deceleration in three planes

Question 10

Capula

Answer 10

Gelatinous structure that encapsulates the cristae and is attached to epithelial lining
Cupola move in the opposite direction of head movement and facilitate deflection of cilia.

Question 11

Kinocilia position for anterior and posterior and horizontal canals

Answer 11

In the horizontal canals the kino are oriented toward the utricle while kin of ant and post canals are oriented away from the utricle
This endolymph toward utricle will depolarize the horizontal canal.
Movement away from the utricle will depolarize ant and post canals

Question 12

Ant and post canals

Answer 12

Sensitive to roll and pitch movements the differential input codes for angular movement

Question 13

Vestibular nuclear complex

Answer 13

Located dorsally in the pons and medulla between lateral part of 4th vent and inferior cerebellar peduncle.

Question 14

Division of vestibular nerve as it enters the brain stem

Answer 14

It splits into ascending fibers and descending fibers

Ascending go to the superior vestibular nucleus, and descending go to the medial and inferior nuclei

Question 15

Vestibular fiber trends

Answer 15

Kinetic labyrinth fibers primarily go to the superior and medial nuclei while static lab fibers will go to the medial and inferior nuclei

Question 16

Commissural connections

Answer 16

Between vest nuclei on either side for comparison of information coming from both sides
These connections also allow for vestibular compensation where postural reflexes are recovered after trauma or disease.

Question 17

Vestibular input

Answer 17

From the cerebellum- floculonodular lobe to sup, med and inf nuc, lateral vermis to the lateral nuc, fstigial nuc to the lat and inferior vest nuclei
Spinal cord: proprioceptive info from spinovestibular tract.
Oculomotor system: accessory optic system.

Question 18

Vest output

Answer 18

To the cerebellum , spinal cord and oculomotor system

Minor output to the insular cortex via thalamus.

Question 19

Medial vestibulospinal tract

Answer 19

Travels via the MLF to the cirvical spine and innervates the medial group of motor neurons in the anterior horn of the spinal cord.
Involved in integration of head and eye movements associated with changes in body position.
Arises from medial and inferior vest nuc and has crossed and uncrossed fibers.

Question 20

Lateral vestibulospinal tract

Answer 20

Involved in adjusting trunk position and orientation in respons to input from the static and kinetic labyrinths.
Travels the length of the sp crd, innervates medial and lateral groups of the ventral horn
Facilitates muscles that maintIn upright posture and balance

Question 21

Vestibuloocular system

Answer 21

Stimulation of semicircular canals causes conjugate eye movements in the same plane as the canal
Stim of horizontal canal causes eye movement in a horizontal plane
Enables movement of eyes such that focus on an object can be maintained even when the head is in motion.

Question 22

Vestibulo-ocular reflex

Answer 22

Ipsilateral projections are inhibitory and contra lateral projections are excitatory
3 neuron reflex arc- primary afferent, vestibular nuclear neuron, oculomotor motorneurons.
Projections from med and sup vest nuc project to oc mot nuclei via MLF
This functions to coordinate functionally and link pairs of eye muscles.

Question 23

Damage to the vestibular system

Answer 23

Vertigo, ataxia, nystagmus, nausea and vomiting

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