Anatomy, Physiology and Psychophysics of Hearing, Auditory scales

Question 1

does perception always match the articulatory or acoustic domain

Answer 1

perception doesn’t always match articulatory or acoustic domain

Question 2

the hearing organ

Answer 2

ear

Question 3

the external ear is made up of what 3 things

Answer 3

auricle (pinna)
meatus (ear canal)
tympanic membrane (ear drum)

Question 4

auricle

Answer 4

• pinna
• localize sound
• important to evolution

Question 5

meatus

Answer 5

• ear canal
• about 2.5cm long
• 0.9mm
• 1/4 wavelength resonator
• amplifies frequencies between 2,000 Hz and 5,000 Hz

Question 6

tympanic membrane

Answer 6

• ear drum

- works like a loud speaker or microphone membrane

Question 7

The middle ear is made up of what 3 things

Answer 7

• malleus
• incus
• stapes

Question 8

what ossicle connect directly to outer ear

Answer 8

malleus

Question 9

which ossicle connects directly to inner ear

Answer 9

stapes

Question 10

what is fluid in the inner ear called

Answer 10

lymphatic fluid inside the inner ear

Question 11

pressure increase in middle ear

Answer 11

Ossicles function like a cone: from large surface (tympanic membrane) to smallest surface (stapes)

Question 12

how do we avoid reflection form occurring in ear

Answer 12

pressure increase is necessary to generate the necessary activation of the liquid (otherwise reflection would occur)

Question 13

how does the middle ear performs a kind of “volume control”

Answer 13

the muscles of malleus can be tensed, resulting in a low frequency damping

Question 14

how are middle ear muscles activated

Answer 14

neural impulses

Question 15

when are middle ear mucscles activated

Answer 15

• loud noise

- before you speak to protect against own voice

Question 16

is the middle ear completely airtight

Answer 16

no

Question 17

what allows pressure equalization in middle ear

Answer 17

eustachian tube

prevents feeling of pressure in the ear

Question 18

cochlea

Answer 18

part of the inner ear relevant for hearing -> sound waves are transformed into neural impulses

Question 19

parts of basilar membrane

Answer 19

• Upper: Scala vestibuli
• Lower: Scala tympani
• These two passages meet at the apex in the helicotrema

Question 20

physiology of hearing

Answer 20

• The pressure waves from the middle ear (stapes) reach the cochlea through the oval window -> longitudinal pressure waves are generated in internal ear fluid through scala vestibuli to the apex
• These pressure waves return via scala tympani to the round window

Question 21

Round window serves as

Answer 21

pressure release, since the fluids are incompressible

Question 22

Organ of Corti consists of

Answer 22

the tectorial membrane, the hair cells and a number of additional supporting cells

Question 23

Unlike the basilar membrane, the tectorial membrane

Answer 23

does not cover the whole width of the cochlea, but only partly overlaps the basilar membrane

Question 24

are the basilar and tectoral membrane

Answer 24

One edge of the tectorial membrane is attached to the basilar membrane

Question 25

the outer hair cells are coded in ______

Answer 25

3 rows tallest to shortest along basilar membrane

Question 26

how many outer hair cells are there

Answer 26

about 20 000

Question 27

the outer hair cells rest upon the __________

Answer 27

basilar membrane

Question 28

inner hair cells transmit _____-____

Answer 28

sound info to the brain

Question 29

outer hair cells go tallest to shortest in which direction

Answer 29

apex -> base

tall -> short

Question 30

brain sends signals to outer hair cells that _____

Answer 30

move basilar membrane

Question 31

actual transmission of information to the brain is done by ________

Answer 31

the inner hair cells

Question 32

Outer hair cells can be controlled by …

Answer 32

the brain via a feedback loop

Question 33

how many inner cells are there

Answer 33

Around 3500 inner hair cells

Question 34

what do inner hair cells do

Answer 34

he conversion of the mechanical movement of the basilar membrane into neural impulses

Question 35

how are inner hair cells organized

Answer 35

a single row inside the organ of corti

Question 36

each inner hair cell is linked to how many nerve cells

Answer 36

1 inner hair cell links to about 1o nerve cells

Question 37

what is located on the top of the inner hair cells main cell body

Answer 37

stereocilia

Question 38

Frequency information is encoded in what manner

Answer 38

tonotopic (each area of reach their maximum displacement for different frequencies -> causing the nerve cells to fire at different frequencies)

Question 39

the basilar membrane acts as a mechanical …

Answer 39

fourier transformation

Question 40

oto-acoustic emissions

Answer 40

the change of shape of the outer hair cells results in a specific movement of the basilar membrane

Question 41

oto-acoustics were discovered by who

Answer 41

Discovered by Kemp (1978) who projected short signal impulses into the ear -> with some delay the ear produced an echo of the impulses

Question 42

Kemp experiment results

Answer 42

echo occurred much later and much stronger (higher amplitude) than expected by the reflective loop of the ear (external ear -> internal ear -> external ear) -> OAE’s are a reaction of the ear itself (including the brain)

Question 43

what is application of oto-acoustics

Answer 43

babies and coma patients who cannot give verbal response