the ear

Question 1

What is neuroplasticity?

Answer 1

the brain’s ability to change through experience

Question 2

What happens in normal hearing regarding hearing and speech?

Answer 2

first comes hearing then speech

Question 3

What happens in post-lingual deafness regarding hearing and speech?

Answer 3

there is speech but no hearing (lose hearing after speech development)

Question 4

What happens in pre-lingual deafness regarding hearing and speech?

Answer 4

no hearing and no speech

Question 5

How is sound amplified in the ear?

Answer 5

• pinna: 10-15dB (but specific to certain frequencies)
• ear canal: 10dB
• tympanic membrane and ossicles: 18 times (due to different in surface area between the tympanic membrane and ossicles)

Question 6

Where do you find endolymph (1)?

where do you find perilymph (2)?

Answer 6

1. -cochlear duct
   - semi-circular ducts
2. -scala vestibuli
   - scala tympani

(maybe more?)

Question 7

What is the chemical property of endolymph that is important in creation of AP?

Answer 7

high in potassium

Question 8

What is sound energy?

Answer 8

wave form contractions and refractions in air and then fluid: causes vibrations on basilar membrane

Question 9

What are the different hair cells involved in hearing?

Answer 9

• inner hair cells: responsible for signal transduction: have stereocillia that connect onto tectorial membrane
• outer hair cells: three rows

Question 10

What happens with at basilar membrane when sound is heard?

Answer 10

• movement of basilar membrane: causing shearing force of hair cells onto tectorial membrane
• displacement of stereo cilia and stretch activated: ion channels open and leave potassium into hair cells and there is depolarisation of cell

Question 11

What is tone?

Answer 11

wavelength of particular frequency (complex vibration with repetitive periodic pattern)

Question 12

What is noise?

Answer 12

complex vibration with no repetitive pattern

Question 13

What is the correlation between frequency and wavelength?

Answer 13

lower frequency sounds have longer wavelengths

Question 14

What is the cochlear nerve pathway?

Answer 14

cochlear nucleus - superior olive nucleus - inferior colliculus - medial geniculate nucleus - auditory cortex

Question 15

What are the important areas in the brain in regards to hearing and speech?

Answer 15

• primary auditory cortex
• Wernicke’s area
• Broca’s area
• motor cortex

Question 16

What does Wernicke’s area do?

Answer 16

speech recognition and reception

Question 17

What does Broca’ are do?

Answer 17

speech development

Question 18

How do you test hearing depending on the ages?

Answer 18

• otoacoustic emissions (done at birth)
• auditory brainstem responses (done before 2m)
• visual reinforcement observation audiometry (6-24m)
• conditioned play audiometry (24-48m)
• conventional audiometry (over 42m)

Question 19

What is the normal hearing threshold and when is it considered to be deaf?

Answer 19

• 0dB: normal hearing threshold

- 110dB: stone deaf

Question 20

What is hearing loss due to old age called?

Answer 20

presbyacusis

Question 21

What happens to detection of sound if you only have one functioning ear?

Answer 21

you can’t detect direction of sound

Question 22

What is the non auditory functions of the external auditory meatus?

Answer 22

protecting
cleaning
+ wax waterproofs it

Question 23

What are the names of the middle ear muscles

What are the functions of the middle ear muscles?

Answer 23

Stapedius and tensor tympani

• stiffening
• stapedius is stimulated acoustically

Question 24

what are the different types of hearing pathologies?

Answer 24

• conductive hearing impairment

- sensory-neural hearing impairment

Question 25

What does profoundly deaf mean?

Answer 25

related to degree of hearing loss and may be used to describe born deaf or deafened people

Question 26

What does deafened mean?

Answer 26

people that have become deaf after acquiring spoken and written language and who mainly identifies with hearing people

Question 27

What does hearing loss mean?

Answer 27

describe level of hearing loss

Question 28

What does hard hearing/hearing impaired mean?

Answer 28

person with some degree of hearing loss: mainly older people who have lost their hearing through age

Question 29

What are the Otolith organs comprise of? What do they detect?

Answer 29

- saccules - utricles - detect static/linear accelearation

Question 30

What do they saccules detect? What are they connected to?

Answer 30

- vertical acceleration | - cochlea

Question 31

What do the utricles detect? what are they connected to?

Answer 31

- horizontal acceleartion | - semi-circular canals

Question 32

What are the semi-circular canals comprise of and what do they detect?

Answer 32

-horizontal SCC -superior SCC -posterior SCC -detect angular acceleration (to differentiate between SCC locate bifurcation between superior and posterior SCC)

Question 33

In what are the sensory hair cells embedded in the otolith organs?

Answer 33

gelatinous layer

Question 34

How is the signal created in the otolith organs?

Answer 34

mechanically gated membrane transduction - otoconia: calcium carbonate crystals (striola) resting on otolithic membrane (jelly) -jelly has receptors --> with movement, jelly layer moves forwards --> when stop, the crystal layer tries to move forwards which triggers receptors (bending of the cilium causes depolarisation)

Question 35

Where are the sensory hair cells located in the semi-circular canals?

Answer 35

ampullae

Question 36

How is the signal created in the semi-circular canals?

Answer 36

- endolymph displaces gelatinous mass (cupula: jelly): causes physical strain on 'hair cells': AP - deflection toward kinocilium increases firing, deflection away from kinocilium decreases firing

Question 37

What are kin cilium? | What are stereo cilium?

Answer 37

in cupula of semi-circular canals - kinocilium: tall hair cells - stereo cilium: small hair cells

Question 38

What are the different movements detected by the semi-circular canals?

Answer 38

- yawing motion: horizontal canals (eyes looking over shoulder) - rolling motion: superior canals (ear towards shoulder) - pitching motion: posterior canals (head up and down)

Question 39

What is the vestibulo-occular reflex?

Answer 39

- prevents retinal slip, compensates for head movement | - modulated by cerebellum

Question 40

what are the different phases in eye movement? and why modulates them?

Answer 40

- slow phase: slow drift when tracking object: modulated by vestibule-occular pathway - fast phase: snap back to midline when stop tracking object: modulated by cerebral cortex

Question 41

What is nystagmus?

Answer 41

alternating slow eye movement and rapid saccadic movement

Question 42

What is the vestibule-spinal tract?

Answer 42

- medial VS tract: head position - lateral VS tract: posture and balance - -> both descend ipsilaterally

Question 43

What is Ménière's Disease?

Answer 43

increase in endolymph pressure: disrupts signal transduction and can result in tinnitus, nausea, spontaneous nystagmus

Question 44

What is Benign Paroxysmal Positional Vertigo (BPPV)? | What can help?

Answer 44

- dislodged bits of Otolith stimulate the cupola in posterior SSC causing vertigo - Epley manoeuvre attempts to nudge them back to the vestibule

Question 45

What is motion sickness?

Answer 45

mismatch between data from different sensory modalities + with what the brain expects to happen