JOURNEY THOUGH THE EAR

WAVE LENGTH AND AMPLITUDE

• Frequency:wave length
• Determines pitch
• Amplitude:height of wave
• Determines loudness

JOURNEY THROUGH THE EAR

• Outer ear channels soundwaves
• Sent through auditory canal to ear drum

JOURNEY THROUGH EAR

• Middle ear sends eardrum's vibrations
• Sent through a piston made of three bones
• Piston bones called hammer, anvil, and stirrup

JOURNEY THROUGH EAR

• Vibration causes cochlea membrane to vibrate(oval window)
• This causes fluid in the cochlea tube to move around
• Fluid sends ripple throughout basilar membrane
• This bends haircells that line its surface

TRANSDUCTION

• Hair cell movement triggers impulses in nerve cells
• Axons from nerve cells converge to form auditory nerve
• Auditory nerve sends neural messages to the thalamus
• The thalamus then sends message to temporal lobe's auditory cortex

VOLLEY PRINCIPLE

• Individual fibers in an auditory nerve respond to stimuli
• Do so in successions of rhythmic noise stimulants
• "Volleys" of impulses fired to suit the incoming data

PERCEIVING LOUDNESS

• Brain determines loudness from number of activated hair cells
• For example: a soft sound only activates a few hair cells

PITCH PERCEPTION

• Place Theory
• We hear different pitches
• Different sound waves trigger activity at different places
• Along cochlea's basilar membrane
• Pitch detemined by specific place that generates neural signal

PITCH PERCEPTION

• Frequency Theory
• Brain reads pitch
• By moniotring frequency of neural impulses traveling up auditory nerve
• Basilar membrane vibrates with sound wave
• Which triggers neural impulses to the brain

LOW VS HIGH PITCH

• High pitch
• Explained by place theory
• Low pitch
• Explained by frequency theory