You better be listening… Auditory Senses

Sound Waves Amplitude  Height of wave  Determines how loud Wavelength  Determines pitch  Peak to peak High frequency, waves packed = high pitch Low frequency, loose waves = low pitch

How we hear: Outer Ear  The pinna channels sound waves into the ear  Naturally blocks out ‘background noise’  Sound waves travel through the auditory canal and vibrates the ear drum

How we hear: Middle Ear  The ear drum vibrates and pulses your ossicles Ear Drum

Cochlea  Ossicles vibrate the cochlea  Transduction occurs  When hair cells move in cochlea, it turns sound waves (vibrations) into neural impulses Video of Natural Earing (1:05)

Major Divisions of the Ear  Outer Ear  acts as a funnel to direct sound waves towards inner structures  Middle Ear  consists of three small bones (or ossicles) that amplify the sound  Inner Ear  contains the cochlea that actually transduces sound into neural response

Hearing Loss  Conduction Hearing Loss  Physical damage to ear drum or ossicles  Nerve Hearing Loss  2 ways to damage cochlear hairs  Can’t regenerate hair growth

Sound Location  Figuring out where sound is coming from  seconds

How we do perceive loud?  number of hair cells that move in the cochlea  If hair cells are no longer sensitive to soft noises, they may still be sensitive to loud

How do we perceive pitch?  Place theory  Where the hairs are located correspond to pitch  High pitch; sensitive near the beginning  Low pitch; sensitive towards the end  Frequency theory  number of impulses fired from the auditory nerve