Physiology of hearing and vestibular function
Middle ear impedance matching, endolymph and the endocochlear potential, hair cell transduction, inner and outer hair cells, tonotopy, the central auditory pathway, and the semicircular canals, otoliths and vestibulo-ocular reflex, applied to tuning forks, ototoxic drugs, the head impulse test, calorics and BPPV.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- The middle ear matches impedance between air and cochlear fluid. Without it about 99.9% of sound energy would reflect off the fluid.
- Endolymph in the scala media is high in potassium and sits at +80 mV. This endocochlear potential, made by the stria vascularis, powers hair cell transduction.
- Inner hair cells are the sensors (95% of afferent fibres). Outer hair cells amplify and tune, and generate otoacoustic emissions.
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Sources
- Principles of Neural Science (6th ed.)McGraw Hill (Kandel, Koester, Mack and Siegelbaum, 2021), 2021
- Guyton and Hall Textbook of Medical Physiology (14th ed.)Elsevier (Hall and Hall, 2021), 2021
- Kattah JC et al. HINTS to diagnose stroke in the acute vestibular syndrome. Stroke 2009;40:3504-10Stroke, 2009
- Prezant TR et al. Mitochondrial ribosomal RNA mutation associated with both antibiotic-induced and non-syndromic deafness. Nat Genet 1993;4:289-94Nature Genetics, 1993
- Last updated
- 14 November 2026
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