Hearing fin

Introduction to biophysics of receptors Biophysics of hearing and vestibular sense Lectures on Medical Biophysics Department of Biophysics, Medical Faculty, Masaryk University in Brno

Lecture outline ,[object Object],[object Object],[object Object],[object Object],[object Object]

Biophysics of sensory perception ,[object Object],[object Object],[object Object],[object Object]

Categorising receptors ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Conversion function of receptors ,[object Object],[object Object],[object Object]

Sensory cell ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Biophysical relation between the stimulus and sensation ,[object Object],[object Object],[object Object],[object Object],[object Object]

Adaptation ,[object Object],Adaptation time-course. A - stimulus, B - receptor with slow adaptation, C - receptor with fast adaptation time time time Number of action potentials Stimulus intensity

Biophysics of sound perception ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

M ain characteristics of sound: (tone) pitch, colour and intensity ,[object Object],[object Object],[object Object]

Intensity level ,[object Object],[object Object],[object Object],[object Object]

Loudness, hearing field ,[object Object],[object Object],[object Object],[object Object]

Hearing field Intensity level intensity

Loudness level of some sounds 120 - 130 Jet propulsion 100 - 110 Pneumatic drill 60 - 90 Traffic noise 40 - 60 Normal speech 20 - 30 Forest silence 10 - 20 whispering Loudness level [Ph] Sort of sound

Sound spectrum ,[object Object],[object Object],[object Object],A E I O U ,[object Object]

Biophysical function of the ear The ear consists of outer, m i ddle and inner ear. ,[object Object],[object Object],[object Object],[object Object],[object Object]

Lever system of ossicles. Maleus and incus form an unequal lever (force increases 1,3x). So-called piston transmission. Protection against strong sounds: Elastic connection of ossicles and reflex es of muscles ( m m . stapedius, tensor tympani ) can attenuate strong sounds by 15 dB.

Mechanism of reception of acoustic signals ,[object Object],[object Object],[object Object],[object Object],[object Object]

Organ of Corti ,[object Object],Lamina spiralis

www.sickkids.on.ca/auditorysciencelab/ pictures1.asp. Pictures obtained from SEM. Organ of Corti with rows of hair- cells. Above general view after removal of vestibular (Reissner) and tectorial membrane. Right a detail of hair- cells.

Organ of Corti ,[object Object],[object Object],[object Object],[object Object]

Mechanism of sound perception: Békésy theory of travelling wave. ,[object Object],[object Object],[object Object]

Electric phenomena in sound reception: ,[object Object],[object Object],[object Object],[object Object],[object Object]

Biophysical function of vestibular system ,[object Object],[object Object]

[object Object],[object Object],Biophysical function of vestibular system

Vestibular organ ,[object Object]

Function of crists and cupullae ,[object Object],[object Object]

Statoconia membrane in sacculus ,[object Object]

Author: Vojtěch Mornstein Content collaboration and language revision: Ivo Hrazdira, Carmel J. Caruana Presentation design: - - - Last revision: June 2009

Hearing fin

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Hearing fin