What are the 3 sections of the ear
Outer, middle and inner
What are the structures of the outer ear
Pinna and auditory canal
What is the role of the pinna
Pinna - catches the sound and funnels sound into auditory canal
What is the role of the auditory canal
Auditory canal - resonating tube, amplifies sound, helps funnel sound towards inner ear and tympanic membrane
What are the structures of the middle ear
Occicles
Tympanic membrane (eardrum)
Eustachian tube
What is the role of the Eustachian tube
Connects middle ear to back of nose/throat
Rest state = closed, sneeze/swallow = open
Prevents buildup air pressure/fluid build up
What is the rile ofi the tympanic membrane
Vibrates as air hits, acts as barrier to separate outer and middle ear
What is the role of ossicles (malleus, incus, stapes)
Smallest bones in body
Amplify pressure of sound waves as enter inner ear x20
Stapes connects to superior oval window which vibrates then causes fluidi in inner ear move
What are the structures of the inner ear
Vestibular nerve
Semicircular nerve
Cochlear nerve
Cochlea
How are sound waves transmitted through the ear
1) sound waves enter outer ear through canal to tympanic membrane
2) tympanic membrane vibrates which sends to middle ear ossicles
3) ossicles amplify sound vibrations, send to cochlea (filled with fluid) in inner ear. Basilar membrane partitions upper and lower cochlea
4) vibrations cause fluid to ripple, forms wave along basilar, hair cells near wide end detect high pitch, closer to center detect lower
5) hair cells move up/down stereocillia on tío hair cells bump against overlying structures and bend. Causes channels to open, chemicals into cells creates electrical signal
6) auditory. Nerve carries electrical signal to brain which turns into sound we recognise/understand
What is the role of the cochlear nerve
Takes electrical impulses from cochlea to vestibulocochlear nerve
What is the role of the cochlea
Snail shaped responsible for hearing
Basilar membrane runs between scala media and Scalia tympani (filled with fluid)
Fluid moves which causes stimulation of electrical signal
What is the role of the basilar membrane
Specialised sensory epithelium on Base of organ of corti
Base = narrow/stiff responds to high freq
Apex = wide/loose responds to low freq
What is mechanical-electrical transduction
Hair cells stimulated then opens up sodium channels which causes graded potential then action potential and NS activated
Electrical signals then travel from organ of corti to brain via cochlea nerve
What is the role of a cochlea implant
Sends sound past the damaged part of ear straight to the cochlear nerve
What is the role of the vestibular nerve
Takes electrical impulses from semicircular canals to vestibulocochlear nerve
What is the role of the semicircular canals
Bony structures in innermost inner ear
3 fluid filled canals of bony labyrinth
Lined with cilia (moves when head moves)
Signals communicated to Brian
Responsible for BALANCE
What are the main categories of hearing loss
Conductive
Sensorineural
Mixed
What is conductive hearing loss
Sound waves blocked travelling to outer/middle ear to the inner ear
What is sensorineural hearing loss
More permanent damage to inner ear
What are issues causing conductive hearing loss in outer ear
Blockage of ear eg. Earwax
Infection eg. Swimmers ear
Auditory canal tumour
Abnormal bone growth in ear canal
What ate issues causing conducive hearing loss of middle ear
Perforated/scarring of ear drum
Cholesteatoma - extra cells
Otosclerosis. Stapes or stirrup bone in middle ear fuses with bones around it and fails to vibrate well
What is Otitis media
AKA glue ear
Eustachian tube blocked then allows fluid from nasal cavity enter middle ear and does not allow fluid to drain
Can contribute to delay in development S+L skills
Wat are the issues causing sesnorineural hearing loss
Viral infections eg. Rubella
Congenital stroke damage to cochlea or auditory cortex
Disease
Noise induced
Bacterial meningitis
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Anatomy32
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The Nervous System83
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The Heart/circulation37
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Head And Neck Physiology19
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Facial Muscles / Muscles Of Mastication27
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Cranial Nerves24
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Head And Neck Anatomy31
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Pharyngeal Area5
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Muscles In Typical Swalowing9
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Speech As Sound (waves)0
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Speech As Sounds (waves)26
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Hearing25
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Typical EDS50
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The Larynx And Respiration27
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EDS Difficulty Through Lifespan48
