hearing and balance

Question 1

inner ear

Answer 1

• vestibule of the ear
• semicircular canals
• cochlea

Question 2

cochlea

Answer 2

auditory portion of the ear

Question 3

organ of hearing

Answer 3

organ of corti

Question 4

membranes separating perilymph fluid

Answer 4

• vestibular membrane
• tympanic membrane

Question 5

hearing process

Answer 5

• hair cells vibrate
• signals sent to auditory neurons via neurotransmitters
• forms the cochlear portion of CNVIII
• info to CNS

Question 6

auditory pathway

Answer 6

Question 7

direction of sound auditory pathway

Answer 7

Question 8

quality of sound auditory pathway

Answer 8

Question 9

primary auditory cortex a1

Answer 9

• superior temporal gyrus, close to the lateral fissure
• topographical map of the cochlea
• low frequency anterior area of a1 (apex of cochlea)
• high frequency posterior area of a1 (base of cochlea)

Question 10

secondary auditory cortex a2

Answer 10

• posterior to a1
• on the superior temporal gyrus, includes Wernicke’s area
• analyzes acoustic stimuli at a higher neuronal level (recognition and interpretation of sounds on the basis of past experience)

Question 11

ablation of the auditory cortex result

Answer 11

inability to distinguish the temporal order of sound

Question 12

ablation

Answer 12

surgical removal

Question 13

types of hearing loss

Answer 13

• conductive hearing loss
• sensorineural hearing loss

Question 14

conductive hearing loss

Answer 14

• problems in the external ear (blockage) or middle ear (otitis, glue ear, damaged ossicles)
• caused by fluid, allergies, foreign objects, ruptured eardrum, impacted ear wax

Question 15

sensorineural hearing loss

Answer 15

• malfunction of the inner ear (cochlea)
• at the level of hair cells or the auditory nerve
• rarely caused by damage to auditory brain
• caused by again, toxicity, loud noise, blast/explosion, tumors

Question 16

vestibular apparatus

Answer 16

• balance
• spatial orientation

Question 17

3 sources of sensory information in equilibrium maintenance

Answer 17

• eyes
• propioception
• vestibular system

Question 18

components that deal with chaotic movement information

Answer 18

• static labyrinth
• kinetic labyrinth

Question 19

static labyrinth

Answer 19

• linear acceleration and spatial orientation
• otolith organs

Question 20

kinetic labyrinth

Answer 20

• angular acceleration
• semi-circular canals on 3 planes that make 90 degree angles with each other
• cupula covers crista ampullaris on the ampulla
• movements of endolymph stimulate bending of cupula
• movement of cupula stimulates movement of hair cells
• movement of hair cells detect head movements

Question 21

otolith organs

Answer 21

• 2 endolymph containing chambers
• utricle and saccule (vestibule)
• contain macula that respond to endolymph movements

Question 22

macula

Answer 22

• clusters of hair cells
• detect linear movements and proprioception of the head

Question 23

utricle

Answer 23

• posterior part of the vestibule
• communicates with semi-circular canals on one end and saccule on the other
• detect movements in the horizontal plane

Question 24

saccule

Answer 24

• anterior part of the vestibule
• smaller than utricle
• joins the utricle and communicates with the cochlea
• detect movements in the vertical plane

Question 25

semi-circular canals

Answer 25

- membranous channels filled with endolymph - located on 3 planes, make 90 degree angles with each other

Question 26

ampulla

Answer 26

terminal part of each semicircular canals

Question 27

crista ampullaris

Answer 27

a cluster of hair cells on each ampulla

Question 28

cupula

Answer 28

gelatinous structure covering crista ampularis

Question 29

vestibular pathway (elongated)

Answer 29

- vestibular nerve input from crista ampullares, semicircular canals, utricle, saccule - info to superior vestibular nucleus of bechtrew, medial vestibular nucleus of schwalbe, inferior vestibular nucleus of roller, lateral vestibular nucleus of dieters

Question 30

pathways that project from vestibular nuclei to the cerebellum function

Answer 30

joint modulation of balance by the cerebellum and vestibular system

Question 31

vestibular pathway (simplified)

Answer 31

Question 32

illnesses of balance

Answer 32

- peripheral vertigo - benign paroxysmal positional vertigo (bppv) - central vertigo

Question 33

peripheral vertigo

Answer 33

- symptoms are a result of inflammation - labyrinthitis - vestibular neuritis - menieres disease - caused by high pressure of endolymph

Question 34

labyrinthitis

Answer 34

inflammation of the inner ear labyrinth and vestibular nerve

Question 35

vestibular neuritis

Answer 35

inflammation of vestibular nerve

Question 36

menieres disease

Answer 36

due to bacterial and viral infections, metabolic disorders, autoimmune disease

Question 37

benign paroxysmal positional vertigo

Answer 37

- most common cause of vertigo - small crystals break free and float around freely within the semi-circular canals - disturbance of the otolith particles

Question 38

central vertigo

Answer 38

- affects the pathways of the vestibular system - very rare - most common symptom is accompanying migraine