Auditory System

Question 1

what is sound?

Answer 1

waves of compressed and expanded air, usually in the form of vibrations

Question 2

loudness is determined by

Answer 2

magnitude of pressure differences (wave amplitude)

Question 3

pitch is determined by

Answer 3

speed at which pressure changes (wave frequency)

Question 4

air molecules get ___ at higher pressure areas of the ear

Answer 4

compressed

Question 5

what is the approximate sound range for humans?

Answer 5

2-20000Hz

Question 6

humans can detect sound of ___ frequency ranges

Answer 6

4

Question 7

what is the function the outer and middle ear?

Answer 7

amplify sound

Question 8

what is the external structure of the ear called? what is its function?

Answer 8

Pinna; funnelling sound onto tympanic membrane

Question 9

what is the function of the external auditory canal?

Answer 9

funnel sound onto tympanic membrane

Question 10

when sound reaches the tympanic membrane, what happens to it?

Answer 10

starts to vibrate

Question 11

vibration of the tympanic membrane causes the movement of __

Answer 11

auditory ossicles

Question 12

what are the middle ear bones (auditory ossicles? )

Answer 12

malleus, incus, stapes

Question 13

what separates the outer from middle eat

Answer 13

the tympanic membrane

Question 14

the movement of the ossicles causes amplification of sound so that when it reaches the oval window, it is __X louder than it was at the tympanic membrane

Answer 14

20

Question 15

what causes the amplification of sound by the ossicles?

Answer 15

their leverage

Question 16

tympanic vibrations are very dependent of __balance between middle and outer ear

Answer 16

pressure

Question 17

how can pressure balance be restored when in a plane and the pressure in the middle ear is too high?

Answer 17

swallowing, because of the Eustachian tube that connects the throat to the middle ear will relive the pressure

Question 18

vibrations of the oval window cause pressure waves of ___ in the ___ to the__ and onto the ___

Answer 18

perilymph in the scala vestibuli; scale tympani; round window

Question 19

pressure waves deform the walls of the __ and cause pressure waves in the ___, which falls the ___ duct

Answer 19

scala vestibuli, endolymph, cochlear

Question 20

pressure waves in the endolymph lead to vibrations of the ___ membrane, and different parts may move depending on __

Answer 20

basilar; sound pitch (frequency of waves)

Question 21

what is the cochlea?

Answer 21

complex set of fluid-filled ducts

Question 22

what are the 2 labyrinths of the cochlea?

Answer 22

bony and membranous

Question 23

what fluid is contained in the bony labyrinth?

Answer 23

perilymph

Question 24

what fluid is contained in the membranous labyrinth?

Answer 24

endolymph

Question 25

the endolymph is rich in what ion?

Answer 25

K+

Question 26

the two membranes that separate the 2 labyrinths are

Answer 26

vestibular and basilar membrane

Question 27

what are the 2 ducts of the bony labyrinth?

Answer 27

1. scala vestiboli | 2. scala tympani

Question 28

what is the 1 duct of the membranous labyrinth?

Answer 28

1. cochlear duct

Question 29

vibration of the basilar membrane causes bending of __

Answer 29

stereocillia

Question 30

stereocillia contain ___ gated ion channels connected __

Answer 30

mechanically; tip-link proteins

Question 31

t/f bending of stereocillia can either open or close mechanically gate ion channels

Answer 31

true

Question 32

when mechanically gated ion channels are opened, ___ rushes in, causing __

Answer 32

K+; depolarization

Question 33

membrane depolarization causes the influx of __ ions and graded release of __

Answer 33

ca2+ ; NT glutamate

Question 34

release of glutamate depolarizes the ___ which causes __

Answer 34

primary sensory neuron; action potential

Question 35

hair cells pert rude into the __

Answer 35

endolymph

Question 36

resisting on the basilar membrane is the ___ which contains inner ___ cells that act as ___

Answer 36

organ of corti; hair; sensory receptors

Question 37

the stereocillia of hair cells are embedded in the ___

Answer 37

tectorial membrane

Question 38

hair cells are contacted by the dendrites of ___ neurons

Answer 38

primary sensory neurons

Question 39

___ determines which hair cells depolarize

Answer 39

sound pitch

Question 40

high-pitch sounds activate hair cells at the __ of the cochlea

Answer 40

base

Question 41

low-pitch sound activate hair cells at the __ of the cochlea

Answer 41

apex

Question 42

___ determines the amount of hair cell depolarization, glutamate release and action potential frequency of first order auditory neutron

Answer 42

sound amplitude (loudness)

Question 43

auditory pathways are __

Answer 43

polyneuronal

Question 44

auditory pathways have relays in the ___, ___ and ___ before termination in the ___

Answer 44

brainstem (cochlea nuclei, inferior livery nucleus), midbrain (interior colliculus) and thalamus (medial geniculate nucleus), primary auditory cortex

Question 45

the inferior olivary nucleus is important to ___

Answer 45

sound localization

Question 46

the inferior olivary nucleus detects timing changes in ___ arriving at the 2 ears

Answer 46

action potential

Question 47

the primary auditory cortex is located in the __ lobe

Answer 47

temporal

Question 48

the primary auditory cortex is responsible for __

Answer 48

conscious awareness of sound

Question 49

information from the base and apex of the cochlea reaches ___ sides of the auditory cortex (___ organization)

Answer 49

opposite ; topographical

Question 50

higher order sound processing is done in the

Answer 50

auditory association area

Question 51

sounds from the base of the cochlea go to the __ part of the auditory cortex

Answer 51

medial

Question 52

sounds from the apex of the cochlea go to the __ part of the auditory cortex

Answer 52

lateral

Question 53

the vestibular apparatus is part of the __

Answer 53

labyrinth

Question 54

what is the vestibular apparatus?

Answer 54

series of fluid-filled tubes in the inner ear (sometimes groups with cochlea as part of labyrinth)

Question 55

what are the 2 main components of the vestibular apparatus?

Answer 55

1. semicircular canals | 2. otolith organs

Question 56

what is the fluid the vestibular apparatus?

Answer 56

same endolymph as cochlea

Question 57

what are the 2 otolith organs?

Answer 57

utricle and the saccule

Question 58

what is the function of the vestibular apparatus?

Answer 58

detection of rotational and linear accelerations of the head

Question 59

what is the function of the semicircular canals?

Answer 59

detect rotational acceleration along 3 perpendicular axes

Question 60

semicircular canals have hair cells in the ___ and stereocillia in the __

Answer 60

ampullae; cupula

Question 61

what are the cupola of the semicircular canals?

Answer 61

gelatinous mass

Question 62

what are the ampullae of the semicircular canals?

Answer 62

bulges

Question 63

what happens in the inner ear when the head rotates?

Answer 63

1. endolymph puts pressure on cupola, bending stereocillia, cation channels are opened or closed depending on direction of rotation, hair cells are either de- or hyper polarized, increase or decrease in NT and frequency of AP

Question 64

the otolith organs detect ___

Answer 64

horizontal accelerations of head in horizontal or vertical directions

Question 65

the utricle responds to accelerations in the __ plane

Answer 65

horizontal

Question 66

the saccule responds to accelerations in the ___ plane

Answer 66

vertical

Question 67

sterecillia of hair cells in the utricle and saccule are ensheathed in a ___ substance containing ___

Answer 67

gelatinous (otolith membrane) ; otoliths

Question 68

otoliths respond to ___ force and cause ___ of hair cells cilia

Answer 68

gravitational