2. Hearing Flashcards
Nature of sound:
sound caused by…
That are characterised by…
simplest sound wave is…
air pressure waves
amplitude (dB) - loudness
Frequency (Hz) - pitch
Phase - position within a cycle
a pure tone - sine wave
Nature of sound:
sound caused by…
That are characterised by…
simplest sound wave is…
air pressure waves
amplitude (dB) - loudness
Frequency (Hz) - pitch
Phase - position within a cycle
a pure tone - sine wave
human hearing range is …
20-20,000 Hx
Typical vocal range…
80-1100Hx
Nature of sound:
complec sounds can be built up from…
a series of sine waves with varying amplitudes, frequency and phase
can be decomposed into components by Fourier analysis
Nature of sound:
what is the fundamental?
What are complex sounds made up of?
fundamental = lowest frequency component of a complex sound
many complex sounds are made up of harmonics, - integer multiples of the fundamental
Basic physiology of the ear
components of the OUTER EAR
Pinna
- increases the sound amplitude
- Helps determine the direction from which a sound is coming form
External auditory canal
- provides protection
- increases the sound amplitude
Eardrum (tympanic membrane)
- vibrates in response to sound waves
Moves bones in the middle ear
Basic physiology of the ear
Components of the MIDDLE EAR
ossicles
- Malleus
- Incus
- Stapes
smallest bones of human body
ossicles transmit the vibrations of the eardrum in to the cochlea through lever actions
They also provide protection against high amplitude sounds
- muscles attached to the ossicles restrict the bones’ movements
Basic physiology of the ear
components of the INNER EAR
semicircular canals
- important for vestibular sense (sense of orientation)
Cochlea
- contains auditory sensory receptors
Basic physiology of the ear
The cochlea
- oval window
The cochlear is filled with a watery liquid that moves in response to the vibrations coming from the middle ear
oval window
- membrane covering opening in the cochlea
- the stapes is attached directly to oval window (where the vibrations get into the cochlea
- much smaller than eardrum - size difference further helps amplify sounds waves
Basic physiology of the ear
The cochlea canals
three canals of the cochlear
- vestibular canal
- tympanic canal
- cochlear duct
separated by
- Reissner’s membrane
- basilar membrane (on which hair/auditory receptor cells located in cochlear duct)
Basic physiology of the ear
The cochlea canal and membrane orientation/order
vestibular canal > Reissner's membrane >> cochlear duct >>> Basilar membrane >>>>Tympanic membrane
Basic physiology of the ear
vibrations to neural signals. HOW?
the three membranes vibrate in response to vibrations of the oval window
Wen the basilar membrane vibrates, hair cells are also set in motion
converts the vibrations in to neural signals
the auditory cortex
What auditory tasks can be performed without the auditory cortex present?
- onset of sound
- changes in sound intensity
- Changes in sound frequency
Typical vocal range…
80-1100Hx
Nature of sound:
complec sounds can be built up from…
a series of sine waves with varying amplitudes, frequency and phase
can be decomposed into components by Fourier analysis