Ch 11: auditory and vestibular systems

Question 1

pinna (auricle)

Answer 1

• located in outer ear
• captures sound waves

Question 2

auditory canal

Answer 2

• located in outer ear
• transmits sound to tympanic membrane

Question 3

bones of middle ear

Answer 3

malleus, incus, stapes

Question 4

eustachian tube

Answer 4

• middle ear
• connects middle ear to nasopharynx
• controls middle ear pressure

Question 5

attenuation reflex

Answer 5

contraction of tensor tympani and stapedius with loud sound to diminish sound transmission

Question 6

bony labyrinth

Answer 6

• inner ear
• contains perilymph

Question 7

membranous labyrinth

Answer 7

• inner ear
• contains endolymph
• contains receptors for hearing and equilibrium

Question 8

cochlea

Answer 8

• used for hearing
• three fluid-filled channels (scali)

Question 9

scala vestibuli

Answer 9

filled with perilymph (high K+, low Na+)

Question 10

scala media (cochlear duct)

Answer 10

filled with endolymph (low K+, high Na+)

Question 11

scala tympani

Answer 11

filled with perilymph

Question 12

inner ear sound wave transmission

Answer 12

oval window → scala vestibuli → apex → scala tympani → round window

Question 13

organ of corti

Answer 13

sits on basilar membrane, contains hair cells

Question 14

stereocilia

Answer 14

hair-like microvilli on hair cells arranged in graded heights

Question 15

hair cells

Answer 15

• auditory receptors
• each cell contains 10-300 stereocilia
• do not generate action potential (not neurons)

Question 16

inner hair cells

Answer 16

one row

Question 17

outer hair cells

Answer 17

three rows

Question 18

hair cell transduction

Answer 18

stereocilia bend c increase rate of channel opening → increase K+ influx → depolarization → Ca2+ channels activated → Ca2+ influx → release of glutamate

Question 19

outer hair cell function

Answer 19

amplify signals of inner hair cells

Question 20

sound wave transmission in the middle ear

Answer 20

tympanic membrane → malleus → incus → stapes → vestibular (oval) window

Question 21

auditory pathway

Answer 21

spiral ganglion → ventral cochlear nucleus → superior olive → inferior colliculus → medial geniculate nucleus → auditory cortex

Question 22

phase locking

Answer 22

consistent firing of a cell at the same phase of a sound wave

Question 23

low frequencies

Answer 23

phase locking

Question 24

intermediate frequencies

Answer 24

phase locking and tonotopy

Question 25

high frequencies

Answer 25

tonotopy

Question 26

vestibular labyrinth

Answer 26

equilibrium

Question 27

otolithic organs

Answer 27

utricle and saccule

Question 28

macula

Answer 28

sensory epithelium on otolithic organs

Question 29

utricular maculae orientation

Answer 29

horizontal

Question 30

saccular maculae orientation

Answer 30

vertical

Question 31

semicircular ducts

Answer 31

- detect angular acceleration/deceleration - located in semicircular canals

Question 32

ampulla

Answer 32

- enlarged end of canals - filled with endolymph

Question 33

crista

Answer 33

hair cells of ampulla

Question 34

cupula

Answer 34

gelatinous material covering crista

Question 35

central vestibular pathway

Answer 35

semicircular canals → vestibular nucleus → cranial nerve nuclei (III, IV, VI) → extraocular muscles

Question 36

the scala vestibuli and the scala media (cochlear duct) are separated by the ________

Answer 36

Reisnner's (vestibular) membrane

Question 37

the scala media and the scala tympani are separated by the ________

Answer 37

basilar membrane

Question 38

the secondary tympanic membrane encloses the _________.

Answer 38

round window

Question 39

most axons innervate _______ hair cells

Answer 39

inner

Question 40

outer hair cells _______ the movement of the basilar membrane using motor proteins called _______.

Answer 40

amplify; prestin

Question 41

the ___________ branch of the vestibulocochlear (VIII) nerve conveys nerve impulses associated with equilibrium

Answer 41

vestibular

Question 42

which cranial nerves are directly involved in the vestibulo-ocular reflex (VOR)

Answer 42

- oculomotor (III) nerve - trochlear (IV) nerve - abducens (VI) nerve