Audition Flashcards
What is the stimuli?
Sound waves (form of mechanical energy)
What is sound?
Pressure waves transmitted through a conducting material (air, water etc)
What is amplitude?
vertical size of sound waves (amount of compression and expansion) (dB) = volume
What is frequency?
number of waves per second (Hz) = pitch
The function of auditory transduction is to…
translate pressure waves into nerve impulses
Describe the pathway of sound waves through the ear
Sound waves into auditory canal
- > eardrum vibrates in response
- > sound to middle ear
- > the 3 little bones vibrate and amplify sound
- > sound waves translated to fluid waves in cochlea (in inner ear, contains basilar membrane)
- > causes hair cells in organ of Corti to bend
- > hair cells synapse with auditory nerve
- > sends impulses via thalamus to temporal lobe
How is high amplitude encoded by the auditory nerve?
High amplitude = hair cells bend more = release more neurotransmitter = higher firing rate in auditory nerve
How is loudness encoded by the auditory nerve?
By firing rate, and signalling from neurons that are only activated by large bend in hair cells = loud noise
How do we locate sound?
Our binaural hearing means that we can detect when sound arrives first and at a higher intensity, indicating this ear is closest to its source
Name 2 types of hearing loss
- Conduction deafness
2. Nerve deafness
What causes conduction deafness? How is this treated?
problems in mechanical system (transmitting sound waves to cochlea)
can be helped with hearing aid
What causes conduction deafness? How is this treated?
Exposure to loud noise results in damage to receptors in inner ear or to auditory nerve
Cannot be helped with hearing aid
