Fisiologi Pendengaran (MDE 2) PDF

Hearing Nurfitri Bustamam, SSi, MKes, MPdKed.  lEARNING OBJECTIVES Describe the components & functions Explain how auditory impulses of the external, middle & inner ear travel from the cochlear hair cells to...

Hearing Nurfitri Bustamam, SSi, MKes, MPdKed.  lEARNING OBJECTIVES Describe the components & functions Explain how auditory impulses of the external, middle & inner ear travel from the cochlear hair cells to the auditory cortex Describe the way that movements of molecules in the air are converted into Explain how pitch, loudness & impulses generated in hair cells in the timbre are coded in the auditory cohlea pathways Explain the roles of the tympanic Describe the various forms of membrane, the auditory ossicles & deafness & the test used to scala vestibule in sound transmission distinguish between them Anatomy of Ear Anatomy of Ear Telinga Luar a. Pinna (ear lobe) - collect & channel sound wave into external auditory meatus (pd bbrp species dpt digerakan, misal pd anjing) - membantu membedakan arah datangnya suara b. External auditory meatus (ear canal) - 2,5 – 3 cm, berbentuk huruf S - tdpt rambut & serumen utk proteksi m tympani c. Membran tympani (ear drum) - a periodik (dpt bergetar sembarang frekuensi) - bergetar bebas jika tekanan di kedua sisi membran sama - diredam dg baik Telinga Tengah - ossicles: maleus-incus-stapes - dindingnya dilapisi mucosa yg mudah menyerap udara - Tuba eustachii: menghubungkan t. tengah dg nasofaring, berfungsi utk menyamakan tekanan pd ke-2 sisi m. tympani; terbuka saat menelan, mengunyah, dan menguap. Acute Otitis Media - infeksi telinga tengah, umumnya oleh bakteri - Sering tjd pd bayi & anak, jarang pd dewasa (note: seiring dg pertumbuhan, tuba eustachii melebar shg drainage lbh baik selama ada infeksi sal napas atas) - Infeksi sal napas atas  t eustachii  telinga tengah multiplikasi patogen  leukosit  akumulasi pus  ruptur m tympani ( di US jarang terjadi) - Otitis media perforata (miringotomi): sengaja melubangi m tympani utk mengeluarkan pus - Th/ antibiotik  bakteri, analgesik  nyeri, decongestan  stagnan mucus & swelling - di negara berkembang, pengobatan blm baik  otitis media kronis - Perforasi/scaring m. tympani  some degree of hearing loss - Pathogen dr telinga tengah menginvasi mastoideus  mastoiditis (nyeri telinga, demam, pembengkakan di blkg telinga)  infeksi ke otak mll N. VII. - Th/ antibiotik & mastoidectomy (opening & drainage of mastoid sinuses) Telinga dalam berisi cairan yg inertianya > udara  perlu tekanan yg tinggi utk menggerakannya via: 1. pemusatan energi (m. tympani 22X lbh luas drpd oval window) 2. Ossicles  hukum tuas shg tek meningkat 1,3X. Oleh karena melawan inertia, hanya 60% energi suara dari m tympani yg sampai ke cochlea. Tensor tympani & stapedius - kontraksi t tympani  m tympani kaku - Kontraksi stapedius  kurangi gerak stapes pd oval window - Fungsi: 1. Memperkeras suara lemah jika ke-2 otot tsb berkontraksi bergantian 2. Jika kedua otot tsb berkontraksi bersamaan  kekakuan telinga tengah shg mengurangi transfer energi ke telinga dalam Tympanic reflex/ Attenuation reflex terjadi jika ada rangsang suara >70 dB, tetapi waktu reaksinya 40 – 160 mdt shg hy melindungi telinga dari suara keras yg lama (prolonged) tetapi tidak terhadap suara letusan mendadak. Telinga Dalam - inner hair cells: primary sensory cells that generate action potentials, they stimulate by fluid movement - Outer hair cells jika memanjang, pengaruh getaran m basilar thd inner hair cells berkurang atau sebaliknya karena ada Prestin (motor protein of outer hair cells) (Ganong 2019) - Reseptor pendengaran sangat sensitive shg dpt mendengar bunyi organ-organ internal. Namun, karena adaptasi perifer & sentral, suara tsb tidak terdengar. Pd saat istirahat di tempat sunyi dpt terdengar bunyi jtg. Masking Adanya suara lain mengurangi kemampuan utk mendengar suatu suara sebab reseptor dlm masa refrakter Sound localization ditentukan oleh perbedaan waktu tibanya suara ke telinga, telinga yg lebih dekat ke sumber suara mendengar lbh keras. The detectable time difference,which can be as little as 20 µs (Ganong 2019) Fig. 52-8. Stimulation of the hair cells by the to-and-fro movement of the hairs projecting into the gel coating of the tectorial membrane. Properties of sound waves Pitch (tone) depend on frequency Intensity (loudness) depend on amplitude Timbre (quality) depend on overtones  Frekuensi - telinga manusia dpt mendeteksi 20 – 18.000 Hz - Paling sensitive pd 1000 – 4000 Hz Amplitudo Standard: Acustical Society of American (ASA) & International Standard Organization (ISO) 0 dB (ASA) = auditory threshold for average human = 0,000204 dyne/cm2 Note: 10 dB (10 x lbh keras dr 0 dB), 20 dB (100 x lbh keras dr 0 dB) 0 dB ISO = 10 dB ASA Timbre pure: garputala most sounds: mixture of overtones Pitch discrimination depends on the basilar membrane that vibrate Loudness depends on the amplitudo of the vibration Overtones: many points along basilar membrane vibrate but less intense than fundamental tones  Tonotopycally: auditory cortex mapping Nada yg berbeda akan merangsang tempat yg berbeda di kortex: Low tones  anterolaterlal High tones  posteromedial 1. Tuli hantar (conductive hearing loss) - block normal transfer of vibration from m tympani to oval window, misal impacted cerumen or foreign bodies in ear canal, scarring/perforation m tympani, otitis media, otosclerosis - Gejala: tdk dpt mendengar & berbicara dg suara pelan sebab mendengar sendiri suaranya yg keras - Th/ implantasi artifisial ossicles, hearing aid - Hearing aid: by pass a defective conduction system by amplifying & transmitting soundwaves through the bone to inner ear 2. Tuli saraf (sensory hearing loss) - noise induced hearing loss  at work or in leisure activity - ototoxin: streptomycin, furosemide, cisplatin - tumor vestibulo-cochlea - systemic disease: DM, syphilis - Terapi: cochlear implant (a small, battery-powered devise is inserted beneath the skin behind the mastoid process); regeneration of hair cells of the organ of Corti  stem cell Reversing Hearing Loss With Regenerative Therapy. https://neurosciencenews.co m/regenerative-therapy- hearing-loss-20278/ 33 Penelitian: mencit dipapar musik rock 2000 Hz, 120 dB, selama 24 jam inner & outer hair cells rusak 34 35 36  Presbycusis - gradual hearing loss associated with aging - affects > 1/3 dari org berusia > 75 tahun - gradual cumulative loss of hair cells & neurons - tdk dpt mendeteksi suara konsonan berfrekuensi tinggi: s, sh, f Pemeriksaan ketajaman pendengaran 1. Suara berbisik 2. Garputala (512 Hz): Rinne, Weber, Schwabach Air conduction (aerotympanal), bone conduction 3. Audiometri 37 38 39 Hasil pemeriksaan: 1. Weber: lateralisasi ke kiri 2. Rinne: kanan positif, kiri negatif 3. Schwabach: kanan normal, kiri memanjang Kesimpulan? 40  Audiogram a. nerve deafness b. middle ear sclerosis 41 42 THANKS! CREDITS: This presentation template was created by Slidesgo, including icons by Flaticon, and infographics & images by Freepik.