exam 1 Flashcards
Divisions of the auditory system
- Outer ear
- Middle ear
- Inner ear
- Auditory nerve (8th)
- Central auditory nervous system
Structures part of the outer ear
Pinna & ear canal
Functions of the outer ear
Funnels sound, protects ear
Important notes about outer ear
- Transfer function up to 15-20 dB
- Acoustic vibration
Middle ear functions
- Acoustic energy to mechanical energy
- Impedence matching: 33 dB increase in middle ear
- Acoustic reflex: bilateral response- loud tone in one ear can be heard in both
Eustachian tube states
adult: 45 degrees
child: 180 degrees: the fluid is more hard to drain, more ear infections
normal state: closed
Eustachian tube function
equalize pressure
Cone of light
light on the right means right ear
What color ear is red
Right
What color ear is blue
Left
Cochlea note
High frequencies at the base, low frequencies at the apex
Cochlea functions
- Sheering of hair cells
- Depolarization
- Mechanical energy to hydromechanical
- Movement of basilar membrane
- Tonotopic organization
Inner hair cells
- Passive process of the cochlea
- 1 row
- 3500 in a single row
Outer hair cells
- Active process of the cochlea
- 3 rows
- W shaped
- Embedded in the tectorial membrane
Wavelength
speed of sound/frequency
Condensation
increased air pressure
Rarefaction
decreased air pressure
Frequency
- Cycles per second
- Hz
- high vs low frequency
Period
How long it takes to complete 1 cycle
Decibels
dB SL- sensation level
dB HL- hearing level
dB IL- intensity level
dB SPL- sound pressure level
When you combine 2 simple waves what happens
Complex wave
What is the lowest frequency of a complex wave
Fundamental frequency
What does 0 dB mean?
Reference point for human hearing- does not mean no sound
What bone houses the cochlea?
Temporal
What does the wavelength of a low frequency look like?
Long wave
What does the wavelength of a high frequency look like?
Short wave
Frequency theory
Pattern of discharge codes for frequency
Place theory
Frequency information coded where peak of traveling wave occurs
Phase locking
Neural discharges occur in the same phase as the stimulus-valid up to 4000 Hz
