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5 Acoustics in Biology and Medicine
5.16.4 Light Scattering Detectors
Light is reflected and/or refracted at the interface between two materials with
differing indices of refraction. If that interface is acoustically vibrating, then the
analysis of the light which has interacted at the interface will give information about
the sound.
Acoustical waves traveling over the surface of solids and liquids can be seen and
measured by scattering light off that surface.
Some effects of sound waves in fluids containing biological cells can be analyzed
by scattering light off the surfaces of those cells, which act as viscoelastic liquid
drops in response to sound.
5.16.5 Detectors Using Electron-Phonon Interaction
The distortion of a semiconductor by a sound wave can produce changes in
the electric potential energy experienced by electrons in the conduction band of
the semiconductor. As the sound wave propagates through the semiconductor, it
can even carry bunches of electrons with it. The transfer of sound energy into
kinetic energy of electrons is sometimes put into the category of electron-phonon
interactions (with a phonon being a quantum of sound energy in the solid).
5.17 Biodetectors of Sound
Over billions of years living on a planet with water and air, life systems have evolved
a variety of method to detect sound, letting them communicate with each other, sense
their environment, and search for food. The resulting detectors, or bioreceptors, are
often quite sophisticated, particularly when there is an advanced brain to analyze
the sound.
Animals with sound detection include:
• Marine crustaceans: External array of sensory hair cells and an internal statocyst
are able to hear sound frequencies 30–500 Hz.
• Fish: Fishes have an inner ear and a mechanosensory lateral line system. The
bodies of fish are nearly the same density as the surrounding water, so sounds
easily enter. Hair cells in their inner ear move in response to sound, and send
signals to the fish brain. (The inner ear structure in fish, including semicircular
canals to sense orientation, is a precursor to that of land animals.) If the fish has
an air bladder near the inner ear, the sound vibrations of that bladder will transmit
to the ear, enhancing hearing for the resonance frequencies of the bladder. Fish
also have a set of hair cells near the skin surface on a lateral line system called
5 Acoustics in Biology and Medicine
5.16.4 Light Scattering Detectors
Light is reflected and/or refracted at the interface between two materials with
differing indices of refraction. If that interface is acoustically vibrating, then the
analysis of the light which has interacted at the interface will give information about
the sound.
Acoustical waves traveling over the surface of solids and liquids can be seen and
measured by scattering light off that surface.
Some effects of sound waves in fluids containing biological cells can be analyzed
by scattering light off the surfaces of those cells, which act as viscoelastic liquid
drops in response to sound.
5.16.5 Detectors Using Electron-Phonon Interaction
The distortion of a semiconductor by a sound wave can produce changes in
the electric potential energy experienced by electrons in the conduction band of
the semiconductor. As the sound wave propagates through the semiconductor, it
can even carry bunches of electrons with it. The transfer of sound energy into
kinetic energy of electrons is sometimes put into the category of electron-phonon
interactions (with a phonon being a quantum of sound energy in the solid).
5.17 Biodetectors of Sound
Over billions of years living on a planet with water and air, life systems have evolved
a variety of method to detect sound, letting them communicate with each other, sense
their environment, and search for food. The resulting detectors, or bioreceptors, are
often quite sophisticated, particularly when there is an advanced brain to analyze
the sound.
Animals with sound detection include:
• Marine crustaceans: External array of sensory hair cells and an internal statocyst
are able to hear sound frequencies 30–500 Hz.
• Fish: Fishes have an inner ear and a mechanosensory lateral line system. The
bodies of fish are nearly the same density as the surrounding water, so sounds
easily enter. Hair cells in their inner ear move in response to sound, and send
signals to the fish brain. (The inner ear structure in fish, including semicircular
canals to sense orientation, is a precursor to that of land animals.) If the fish has
an air bladder near the inner ear, the sound vibrations of that bladder will transmit
to the ear, enhancing hearing for the resonance frequencies of the bladder. Fish
also have a set of hair cells near the skin surface on a lateral line system called