sense of hearing - ankara yıldırım beyazıt university sense of hearing . sound waves
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Sinan Canan, PhD sinancanan@gmail.com
The Sense of Hearing
Sound Waves
Pressure waves Compressions/expensions Propagation in 3 dimensions
Sound Waves
Pressure waves Compressions/expensions Propagation in 3 dimensions
Sound waves
Frequency – “tone” [Hz] Amplitude Intensity Timbre
Sound waves
Sound intensity and “decibel” (dB) Hearing treshold = 0 dB = 1.10-12 W/m2
Bel = log [Pi/Pref] dBel = 10 x log [Pi/Pref]
10 dB = 1.10-11 W/m2 (treshold x 10) 20 dB = 1.10-10 W/m2 (treshold x 100) 30 dB = 1.10-9 W/m2 (treshold x 1,000) 40 dB = 1.10-8 W/m2 (treshold x 10,000) 50 dB = 1.10-7 W/m2 (treshold x 100,000)…
Sound waves
Sound intensity and “decibel”
Source Intensity dB X Treshold Treshold 1.10-12 W/m2 0 100 Rustle of a leaf 1.10-11 W/m2 10 101 Whisper 1.10-10 W/m2 20 102 Regular talk 1.10-6 W/m2 60 106 Intense traffic 1.10-5 W/m2 70 107 Vacuum cleaner 1.10-4 W/m2 80 108 Large orchestra 6,3.10-3 W/m2 98 109.8 Max volume in an MP3 Player 1.10-2 W/m2 100 1010 Front row of a rock concert 1.10-1 W/m2 110 1011 Takeoff of a military jet 1.102 W/m2 140 1014 Eardrum damage 1.104 W/m2 160 1016
Sound waves Hearing loss due to age
Ear
Outer ear Middle ear
Inner ear
Outer ear
Congregating sound Source localization “Transfer function”
Outer Ear– “Transfer Function”
Eardrum
Eardrum
Normal Otitis media
Middle Ear
1. Malleus (hammer) 2. Incus (anvil) 3. Stapes (stirrup) 4. Eardrum 5. Round window 6. Eustachian tube
Middle Ear
1. Malleus (hammer) 2. Malleus ligament 3. Incus (anvil) 4. Incus ligament 5. M. stapedius 6. Stapes’ base 7. Eardrum 8. Eustachian tube 9. M. Tensor tympani 10. Chorda tympani
Ossicular reflexes 1. Malleus (hammer) 2. Malleus ligament 3. Incus (anvil) 4. Incus ligament 5. M. stapedius 6. Stapes’ basis 7. Eardrum 8. Eustachian tube 9. M. Tensor tympani 10. Chorda tympani
V
VII
Inner ear
Cochlea
Cochlea
Koklea
Scala vestibuli
Scala tympani
Scala media
Stria vascularis
Organ of Corti
Basilar membrane
Cochlea
Stria vascularis
Cochlea and the Organ of Corti
Organ of Corti
Basilar Membrane
Frequency analysis of sound Frequency selectivity of the basilar membrane
Frequency analysis of sound Frequency selectivity of the basilar membrane
Frequency analysis of sound Frequency selectivity of the basilar membrane
Frequency analysis of sound
Hair cells
Inner hair cells Outer hair cells
Organ of Corti
Hair cells
Tepe bağlantısı miyozin
Kanal
Hair cells
Destek hücreleri Deiter hücreleri
Dış tüy hücreleri İç tüy hücreleri
Destek hücreleri
Hair cells
Hair cells Outer hair cells
Inner hair cell
Hair cells
Outer hair cells: “Cochlear amplificator”
Hair cells
Transmitters of inner hair cells
Hair cells
Transmitters of the outer hair cells
Auditory pathways
Superior olivary
nucleus
Auditory pathways
Superior olivary complex: First comparison of the sounds coming from each ear – source localization Lateral superior olivary nucleus: Amplitude variations in
high pitches Medial superior olivary nucleus: Time delays in lower
pitches
Auditory pathways
Electrocochleogram (ECoG)
Brainstem and cortical auditory
evoked potentials
Auditory pathways Electrocochleogram
Auditory cortex
Auditory cortex
The End...
Music is a higher revelation than all wisdom and philosophy… Ludwig van Beethoven
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