The Auditory System

Question 1

What is a sound wave

Answer 1

Vibrations of air that alternate between regions of compression and non compression (rarefaction)

Question 2

Sound waves are distinguished by their ?

Answer 2

Amplitude and frequency

Question 3

What is amplitude

Answer 3

The height of the waves
Determines intensity (loudness)
Measured in decibels

Question 4

Frequency

Answer 4

Number of waves per second
Measured in hertz
Determines pitch

Question 5

External ear

Answer 5

Receives and transmits sound pressure waves to the middle ear

Question 6

Middle ear

Answer 6

Transfers sound energy from air to the liquid inner ear (turns sound energy to fluid waves)

Question 7

Inner ear

Answer 7

Tranduces signal to a change in membrane potential (converts fluid to a change in membrane potential)

Question 8

The oval and round window seperate…

Answer 8

Seperate air filled middle ear from fluid filled inner ear

Question 9

Malleus, Incus & Stapes pass on vibrations to the inner ear at the …

Answer 9

Same frequency

Question 10

Eustachian Tube

Answer 10

Release a build up of pressure; for ex: in a plane @ high altitudes, you tru to yawn to open that tube to releive pressure

Question 11

External ear consists of: (2)

Answer 11

the outer ear (pinna) and the ear canal

Question 12

What does the penna do

Answer 12

Direct sound waves into the ear

Question 13

That your canal is sealed and it’s internal and by a thin membranous called

Answer 13

Tympanic membrane

Question 14

Sound waves that vibrate the Tympanic membrane move the three middle ear bones at

Answer 14

The same frequency

Question 15

What is the malleus/the hammer connected to?

Answer 15

Tympanic membrane

Question 16

T or F: the incus (anvil) is in the middle

Answer 16

True

Question 17

Stapes (stirrup) is connected to??

Answer 17

The oval window

Question 18

The pressure of the sound waves is _____ by the middle war

Answer 18

Amplified

Question 19

Movement of the bones trigger movement of fluid in the cochlea at

Answer 19

The same frequency

Question 20

The Inner ear consist of two major sensory structures:

Answer 20

The vestibular apparatus and the cochlea

Question 21

Step one of Sound transaction

Answer 21

Soundwaves strike the Tympanic membrane and become vibrations

Question 22

Step two of sound transduction

Answer 22

The sound wave energy is transferred to the three bones of the middle ear which vibrate

Question 23

Step three of sound transaction

Answer 23

The stapes is attached to the membrane of the oval window. Vibrations of the oval window create fluid waves with in the cochlea

Question 24

Step four of sound transduction

Answer 24

The fluid waves push on the flexible membranes of the cochlear duct. Hair cells bend and ion channels open, creating an electrical signal that alters neurotransmitter released

Question 25

Step five of sound transduction

Answer 25

Neurotransmitter release onto sensory neurons creates action potential that travel through the cochlear nerve to the brain

Question 26

Step six of sound transduction

Answer 26

Energy from the waves transfers across the cochlear duct into the Tympanic duct and is dissipated back into the middle ear at the round window

Question 27

Where does sound transaction occur

Answer 27

In the cochlea

Question 28

What are the three fluid filled channels in the cochlea

Answer 28

Top: vestibular duct - consists of perilymph (plasma/CSF) Middle: cochlear duct - consists of endolymph (extracellular fluid very high in K+) Bottom: Tympanic duct - consists of perilymph (plasma/CSF)

Question 29

What happens if fluid waves can’t dissipate back into the middle ear at the round window

Answer 29

The waves will stay in the cochlea

Question 30

Where are high frequency sounds on the basilar membrane

Answer 30

At the stuff end of the basilar membrane near the oval window

Question 31

Where do low-frequency sounds deflect on the basilar membrane

Answer 31

At the apical end close to the end of the basilar membrane

Question 32

Specific populations of hair cells respond to…

Answer 32

Specific sound frequencies

Question 33

Hi and low frequency sounds are specially mapped onto the…

Answer 33

Basilar membrane

Question 34

Spacial coating is preserved in the

Answer 34

Auditory cortex

Question 35

What is included in the organ of Corti (4)

Answer 35

The basilar membrane, tectorial membrane, hair cells, afferent and efferent axons

Question 36

What happens when the basilar membrane is displaced

Answer 36

It moves hair cells which pushed against the tectorial membrane and generate action potential’s in the hair cells out through the axons

Question 37

What is the role of the inner hair sell

Answer 37

To relay information to the brain

Question 38

What is the role of the outer hair cells

Answer 38

To amplify the signal and excite cells more

Question 39

The direction of displacement determines whether hair cells are…

Answer 39

Depolarized or hyperpolarized

Question 40

True or false? Hair cells don’t have axons and don’t generate action potential’s, but they can release neurotransmitters

Answer 40

True

Question 41

What makes up a hair bundle

Answer 41

Stereocilia

Question 42

Why are there sensory and inhibitory synapses onto the hair cells?

Answer 42

Usually to inhibit, allows for by directional flow, so you can get a cleaner sound and drown out others

Question 43

Displacement towards the tallest stereocilia causes?

Answer 43

A depolarization

Question 44

Displacement towards the shortest stereocilia causes what?

Answer 44

Hyperpolarization

Question 45

Where does the ion exchange takes place in the hair cell

Answer 45

Between stereocilium in the tip link

Question 46

What is going on in the tip links at rest

Answer 46

Some channels are open at rest so a little bit of neurotransmitters can be released but there is no obvious noise, just background noise

Question 47

What happens in the hair cells during excitation

Answer 47

More channels open Caption entry depolarizes AP generated

Question 48

What happens to the hair cell during inhibition

Answer 48

The channels clothes. Less cat ion and entry hyperpolarizes the cell. No neurotransmitters are released

Question 49

True or false? Excitation produces more action potential’s then at rest

Answer 49

True

Question 50

What does cranial nerve eight contain

Answer 50

The vestibule or nerve for balance and the cochlear nerve for hearing

Question 51

What is conductive hearing loss

Answer 51

Sound waves are not adequately conducted to the External and middle portions of the ear

Question 52

Sensorineural hearing loss

Answer 52

Sound waves are not translated into nerve signals that are interpreted by the brain as sound sensations

Question 53

Central Hearing Loss

Answer 53

Damage to the nerve pathways between the ear and the auditory cortex or to the cortex itself