Module 3: Audition

Question 1

what are the contested sensory systems

Answer 1

kinesthesioception, proprioception, equilibrioception, thermoception, nociception

Question 2

what is kinethesioception

Answer 2

sensing acceleration

Question 3

what is proprioception

Answer 3

sensation of position

Question 4

what is equilibrioception

Answer 4

sensation of balance

Question 5

what is thermoception

Answer 5

sensation of temperature

Question 6

what is nociception

Answer 6

sensation of pain

Question 7

perception

Answer 7

the process of recognizing, interpreting, and organizing sensory information

Question 8

bottom-up processing

Answer 8

perceptions are built from sensory input

Question 9

top-down processing

Answer 9

interpretation of sensations is influenced by our knowledge, our experiences, and our thoughts

Question 10

what do all sensory pathways require

Answer 10

• a stimulus
• a sensory receptor

Question 11

what are sensory receptors

Answer 11

specialized cells or nerve endings of sensory neurons where sensory impulses originate

Question 12

what is unique about sensory receptors

Answer 12

each one has an adequate stimulus that is unique to that receptor

Question 13

what are the five main types of sensory receptors

Answer 13

• chemoreceptors (respond to chemical ligands)
• mechanoreceptors (respond to mechanical energy)
• thermoreceptors (temperature)
• nociceptors (painful stimuli)
• photoreceptors (light)

Question 14

what is threshold

Answer 14

strength of stimulus sufficient to stimulate a receptor

Question 15

what are the characteristics of sensory systems

Answer 15

• modality
• threshold
• location
• duration

Question 16

what is duration in a sensory system

Answer 16

sufficient time for stimulus to activate

Question 17

adaptation

Answer 17

ability of sensory receptors to adjust to stimulus presence for a long period of time
- slowly response will diminish

Question 18

what is synaesthesia

Answer 18

union of the senses; several sensory systems work in harmony together

Question 19

graphome-color synaesthesia

Answer 19

letters and numbers are coordinated

Question 20

lexical-gustatory synaesthesia

Answer 20

tastes and words are coordinated

Question 21

causes of synaesthesia

Answer 21

developmental, acquired (induced by trauma, neuropathology, or stroke), pharmacological (under effects of halucinogens)

Question 22

what path do sound waves take through the auditory system

Answer 22

sound –> pinna –> outer canal –> tympanic membrane –> vibrations of ossicles –> vibration of membrane & oval window –> cochlea –> basilar membrane moves w/ receptors (hair cells) that are activated by sound waves –> depolarization or hyperpolarization –> auditory nerve –> cochlear nuclei –> superior olive –> inferior colliculus –> medial geniculate nucleus –> primary auditory cortex

Question 23

how do sound waves affect the air

Answer 23

causes compressed and rarified air

Question 24

what frequencies of sound do humans detect

Answer 24

20 Hz - 20 kHz

Question 25

what frequencies is infrasound

Answer 25

< 20 Hz

Question 26

what frequencies is ultrasound

Answer 26

> 20 kHz

Question 27

what is sound intensity perceived as

Answer 27

sound loudness

Question 28

formulas fr intensity

Answer 28

energy / (time * area) power/area

Question 29

what is the threshold of human hearing

Answer 29

0 dB

Question 30

why do we need three little bones in the ear?

Answer 30

it reduces pressure on oval window since the tympanic membrane is a lot bigger

Question 31

what is the auditory canal

Answer 31

closed tube resonator, enhances sounds in 2-5 kHz

Question 32

what kind of sounds are important for humans

Answer 32

speech, music

Question 33

what does the middle ear consist of

Answer 33

tympanic membrane (eardrum), ossicles: malleus (hammer), incus (anvil), stapes (stirrup)

Question 34

how does the ear deal with amplification

Answer 34

pressure oval window is 20x > eustachian tube

Question 35

what is the middle ear filled with, and how is it pressurized?

Answer 35

it is filled with air, and is the same pressure as outside

Question 36

what are the cochlear muscles responsible for

Answer 36

attenuation reflex

Question 37

how does the attenuation reflex work

Answer 37

at 70 - 90 dB the tensor tympani and stapedius muscles contract to accommodate for prolonged loud sounds

Question 38

what is the cochlea filled with

Answer 38

fluid

Question 39

what are the scala vestibuli and tympani filled with

Answer 39

perilymph

Question 40

what is the scala media filled with

Answer 40

endolymph

Question 41

how does endolymph relate to perilymph

Answer 41

endolymph electric potential 80 mV and is more positive than perilymph

Question 42

what does the stria vascularis do

Answer 42

removes potassium to scala media and takes in sodium - active transport

Question 43

what is the shape of the cochlea

Answer 43

wide base --> narrow apex

Question 44

what is the shape of the basilar membrane

Answer 44

narrow at cochlear base --> wide at apex

Question 45

what is the function of the round window

Answer 45

allows fluid to move when the bones tap on the oval window

Question 46

where do high sound frequencies travel

Answer 46

generate a wave that travels up the apex

Question 47

where do low sound frequencies travel

Answer 47

waves vibrate closer to the cochlear base

Question 48

what is the organ of corti

Answer 48

sensory area of cochlea

Question 49

how many inner hair cells and outer hair cells are there

Answer 49

3500 inner cells (1 row) and 15000-20000 outer hair cells (3 rows)

Question 50

what surrounds the somas of hair cells

Answer 50

perilymph

Question 51

how many stereocilia do each hair cell have

Answer 51

100

Question 52

where do afferent axons project to

Answer 52

inner hair cells

Question 53

where do efferent axons project to

Answer 53

outer hair cells

Question 54

what initiates auditory transduction

Answer 54

traveling waves

Question 55

what are the two options for stereocilia's electrical potential

Answer 55

either depolarized or hyperpolarized depending on which direction the hair cells move

Question 56

how is receptor potential generated in hair cells

Answer 56

the back and forth movement between depolarization and repolarization

Question 57

when are MET channels open

Answer 57

when the tip links (elastic filaments) joining the stereocilia are stretched

Question 58

what does the entry of Ca through the MET channels result in

Answer 58

release of neurotransmitter

Question 59

what drives potassium through MET channels into the hair cells

Answer 59

electrical gradient

Question 60

what does the entry of potassium do

Answer 60

drives depolarization

Question 61

what is the function of outer hair cells

Answer 61

cochlear amplifier

Question 62

what do spiral ganglion cells synapse with

Answer 62

95% synapse with inner cell and 5% synapse with outer cells

Question 63

how do outer hair cells work as cochlear amplifiers

Answer 63

if a sound is not sufficient to move the basilar membrane, the brain tells the outer cells to move - when outer hair cells expand they push against the tectorial membrane

Question 64

what happens when outer hair cells contract

Answer 64

they pull the tectorial membrane in and thus move the basilar membrane

Question 65

what function does the Prestin gene have

Answer 65

increases sensitivity to sound

Question 66

how do antibiotics affect sound sensitivity

Answer 66

reduce sound sensitivity

Question 67

what is sound intensity

Answer 67

firing rate of neurons

Question 68

what parts of the brain might be responsible for loss of hearing in one ear

Answer 68

damage to anything below superior olive

Question 69

where does the auditory pathway decussate

Answer 69

superior olive

Question 70

how is the primary auditory cortex organized

Answer 70

tonototopically

Question 71

symptoms of Broca's aphasia

Answer 71

knows what they want to say but can't get it out - search for words, speak slowly

Question 72

symptoms of Wernicke's aphasia

Answer 72

speech is incoherent and makes no sense - have reduced understanding of spoken and written language

Question 73

what are the left hemisphere (specifically Wernicke's area and Broca's area) responsible for

Answer 73

speech perception and production

Question 74

where is Wernicke's area located

Answer 74

posterior part of the superior temporal gyrus

Question 75

where is Broca's area located

Answer 75

inferior frontal gyrus

Question 76

what is the right hemisphere mainly responsible for

Answer 76

processing of tonal stimuli and music

Question 77

ear advantage

Answer 77

infants usually prefer left ear to tones, but right for clicks - the preference disappears with age

Question 78

what is the ventral stream

Answer 78

"what" stream: identity of sound

Question 79

what is the dorsal stream

Answer 79

"where" stream: location of sound

Question 80

steps of the first theory of localization

Answer 80

1. sound reaches left ear 1st 2. action potential --> medial superior olive 3. sound reaches right ear later 4. action potential right ear --> medial superior olive 5. action potentials converge on medial superior olive neurons that respond strongly

Question 81

what is the function of the medial superior olive

Answer 81

coincidence detectors, responding most when excitatory signals from cochlear nuclei

Question 82

what do lateral superior olives encode

Answer 82

they encode sound through interaural intensity

Question 83

what are the steps of LSO neurons encoding sound

Answer 83

1. stronger stimulation --> left ear excites left LSO 2. stimulus inhibits right LSO via MNTB interneurons 3. excitation from left side --> inhibition right side = net excitation --> higher centers 4. inhibition from left side is greater than excitation from right side

Question 84

what is the duplex theory

Answer 84

shape of pinna allows sound to enter the ear canal

Question 85

cause of hearing loss

Answer 85

genetic, environmental (toxic sounds)

Question 86

what does conductive hearing loss entail

Answer 86

sound doesn't get through outer ear canal --> eardrum

Question 87

possible causes of conductive hearing loss

Answer 87

fluid in middle ear, ear infection, perforation, benign tumors, earwax

Question 88

how can conductive hearing loss be corrected

Answer 88

medically/surgically

Question 89

what does sensorineural hearing loss entail

Answer 89

damage to cochlear nerve pathways or to the nerve pathways from the inner ear to the brain

Question 90

possible causes of sensorineural hearing loss

Answer 90

drugs, loud noise, hereditary, aging, head trauma

Question 91

can sensorineural hearing loss be corrected?

Answer 91

no

Question 92

possible corrections for sensorineural hearing loss

Answer 92

hearing aid, cochlear implant (if there are no functioning hair cells with unaffected cochlea), gene therapy from stem cells

Question 93

how do cochlear implants work

Answer 93

bypass the nonfunctional or absent HCs and directly stimulate SGNs - takes advantage of the tonotopic arrangement of the auditory organ

Question 94

how common is genetic hearing loss

Answer 94

50% of hearing loss cases are genetic