Vestibular

Question 1

external auditory Meatus

Answer 1

The sound waves travel through this area and will cause vibrations to occur at the eardrum or the tympanic membrane

Question 2

auditory ossicles

Answer 2

Malleus, incus, stapes
sound amplification

internal to the eardrum and pick up the movement of the tympanic membrane in response to the vibrations and transmits the sound waves to the oval window

There are muscles that attached to the ossicles that helps reflexively dampen the sound and as protection

Question 3

Oval window

Answer 3

transmit sound vibrations into the lymph fluid inside the labyrinth, the cochlea

Question 4

after the sound waves have been transmitted into the fluid of the cochlea,

Answer 4

There are hair cells that send signals to the cochlear nerve.
The pressure is then dissipated at the round window

Question 5

The order of events of sound

Answer 5

auricle
External auditory canal
Tympanic membrane
auditory ossicles
oval Window
Fluid lymph in cochlea
hair cells
Cochlear nerve
Pressure dissipated at round window

Question 6

labyrinth inner ear

Answer 6

Cochlea
Vestibule
Semicircular canals

Question 7

bony labyrinth

Answer 7

within Compact bone
Contains perilymph suspends membranous labyrinth

Question 8

membranous labyrinth

Answer 8

Cochlear duct
Utricle
Saccule
Semicircular canals

Filled with endolymph
Hair cell receptors -bend and send signal frequencies to cranial nerve eight

Question 9

perilymph

Answer 9

Between the labyrinth and the bone

Question 10

endolymph

Answer 10

Inside the membranous labyrinth

Question 11

semicircular canals

Answer 11

Three hollow rings, perpendicular to each other

Anterior (superior)
Lateral (horizontal)
Posterior

receptors detect motion via movement of the endolymph
Only sensitive to rotational acceleration and deceleration

The canals open into the utricle (otolithic organ)
Before you get to the utricle, there is the ampulla which are swellings of each canal that contains a crista

Question 12

crista ampullaris

Answer 12

ampullae contain cristae

supporting cells
Sensory hair cells
Embedded in gelatinous mass called cupula

Movement of the cupula causes hair cells to move and detect movement

Question 13

Hair cells

Answer 13

translate, mechanical force into nerve impulses

Consist of sensory neuron
multiple small stereocilia
a single large kinocilium

Question 14

when the lymph moves, and there is movement towards the kinocilium… along the hair cell

Answer 14

there is going to be an excitatory effect

increased discharge rate of the vestibular nerve
Depolarization happens at a faster rate

Question 15

when the lymph moves away from the kinocillium… opposite direction

Answer 15

Theres going to be an inhibitory effect

Hyperpolarization
Discharge is significantly slow

Question 16

cupula movement

Answer 16

Head moves one way, cupula moves the other

Head stationary, baseline rate of the cell firing

Question 17

Head movement (cupula)

Answer 17

Head moves - fluid lag causes the cupula to bend and move the hair cells

Head movement slowing or stopping- cupula bends in opposite direction

Question 18

Constant movement (cupula)

Answer 18

endolymph moves at the same speed so the hair cells fire at a constant rate

Question 19

orientation of the semi circular canals

Answer 19

Are at 90° to each other
Relays movement from correct plane of motion

Question 20

otolithic organs

Answer 20

utricle
saccule

do not respond to rotation

Respond to head position relative to gravity
Linear acceleration and deceleration

Each sack contains a macula

Question 21

utricle in which plane

Answer 21

Horizontal plane

Question 22

saccule in which plane

Answer 22

Vertical plane

Question 23

Membranous sacs (utricle, saccule) are located between

Answer 23

cochlea And semicircular canals

Question 24

otoliths in the lymph

Answer 24

The movement of the otolith in the lymph moves across the hair cells that causes the bending and the change in the firing rate from the hair cells

Question 25

macula

Answer 25

Hair cells in the gelatinous membrane with calcium carbonate crystals on the top (otoconia) Changes and head position tilt the macula Hair bends due to otoconia displacing the gelatinous mass Bending of the hair stimulates neural firing frequency in cranial nerve 8

Question 26

utricular macula

Answer 26

resides in the floor of the utricle when head is upright Oriented horizontally Maximal response -head upright and bending forward Also response to linear acceleration and deceleration Sagittal plane movement

Question 27

sacular macula

Answer 27

oriented vertically Maximal response - from laterally flex position sideline to standing Frontal plane movement

Question 28

Vestibular cochlear nerve portions

Answer 28

cochlear- portion hearing Vestibular portion- postural control and control of eye movements

Question 29

Vestibular nuclei reside in

Answer 29

brainstem at the Pontomedullary junction contribute to head movement Head position relative to gravity eye movement control when head moves, gaze stabilization Postural adjustments autonomic functions

Question 30

lateral vestibular nucleus

Answer 30

Lateral vestibular spinal tract originates here (medial, postural, balance, tone) Extends length of the spinal cord Regulates lower motor, neurons to postural muscles and limbs and trunk

Question 31

lateral vestibular nucleus

Answer 31

Regulates lower motor neurons to postural muscles and limbs and trunk

Question 32

Medial vestibular nucleus

Answer 32

(and the small portion of the inferior vestibular nucleus) Gives rise to medial vestibular spinal tract Extends into the cervical region and controls the head and neck position (SCM , Traps)

Question 33

The nucleus and the small portion of the superior vestibular nucleus

Answer 33

fibers ascend into the medial longitudinal fasciculus oculomotor ,trochlear, abducens nuclei superior colliculus and cranial nerve 11 nucleus mediate vestibular ocular reflex VOR

Question 34

VOR

Answer 34

eye movements adjust for changes and head position Stabilizes images during head movement dolls eyes gaze stabilization Head turns right - increase signal from right horizontal canal and decreases signal from left horizontal canal Move eyes opposite to direction of the head movement to maintain the visuals stability

Question 35

VOR order

Answer 35

rotational, acceleration or deceleration of the head Receptors in semi circular canals Vestibular nuclei oculomotor nuclei Extra ocular muscles

Question 36

Face tilts down

Answer 36

Anterior Canal stimulated First synapse in the vestibular nucleus is superior Second synapse in the nucleus of cranial nerve three Muscles activated, bilateral superior rectus, and contralateral inferior oblique Movement of the eyes is up

Question 37

Face turns right or left

Answer 37

Horizontal Canal stimulated First synapse in vestibular nucleus is medial Second synapse in nucleus of cranial nerve three and six Bilateral medial and contralateral lateral rectus eye moves horizontal

Question 38

Face tilts up

Answer 38

Posterior canal stimulated First synapse and vestibular nucleus as medial Second synapse and nucleus of cranial nerve three and four Ipsilateral superior oblique and contralateral inferior rectus eyes Move down

Question 39

medial longitudinal fasiculus

Answer 39

connections with extraocular nuclei (3, 4, 6) Regulates eye movements in response to head movements

Question 40

vestibulospinal tracts

Answer 40

postural regulation

Question 41

vestibulocolic pathways

Answer 41

Of the spinal accessory nerve influencing head position

Question 42

vestibulothalamocortical pathways

Answer 42

Conscious awareness of head position and movement

Question 43

vestibulocerebellar

Answer 43

Controls magnitude of muscle responses to vestibular information

Question 44

Vestibular reticular pathways

Answer 44

Influences reticular spinal tracts and autonomic centers for nausea and vomiting

Question 45

semi circular canals are activated by

Answer 45

Rapid rotation Can trigger loss of control, leaning or falling