Auditory sytem Flashcards
What does amplitude and the frequency of the sound waves each determine?
Amplitude = loudness Frequency = pitch
What does the outer part of the ear do?
Amplifies sound pressure for frequencies 2-5 kHz
Focusses waves down tympanic mem to get wave to inner ear
What does the middle part of the ear do?
Contains the tympanic mem which amplifies the sound
What does the inner part of the ear have?
It has specialised sensory hair cells
Describe structural features of the inner ear
3 fluid compartments each with different ionic properties
- vestibular
- tympanic
- basilar
What is the structure of the basilar membrane?
Tapered structure
Narrow at one end then progressively wider
What activates hair cells ?
Sound induce vibration
Give some properties of stereocilia
Deflect don’t bend
Tapered to base = pivot point
Rigid as made of actin
What is the name of the longest stereocilia?
Kinocilium
What charge is endolymph? and why?
Very +ve compare of outside of cell= electrical gradient = K+ enter cell to activate voltage gated ca2+ channels = vesicle fusion and NT release
What do outer hair cells do in response to electrical currents?
Contract and expand (active process)
what does the tonotopic organisation of frequency in the basilar membrane allows us to distinguish?
between different frequencies/pitches
