07 The Ear, Hearing and balance Flashcards
Name the parts of the outer Ear
Pinna - Outside protrusion to amplify sound
Ear canal - Sound waves travel down to the middle ear
Name the parts of the middle Ear
Ear drum / Timpanic membrane - vibrates with sound waves
Ossicles
- Malleus/Hammer
- Incus/Anvil
- Stapes/Stirrup - pass vibrations to inner ear
Eustachian tube - equals pressure either side of ear drum
Name the parts of the inner Ear
Cochlea - looks like a snail shell, full of liquid. Senses vibrations from middle ear or through skull by skull conduction.
Auditory nerve - sends electrical signals from the cochlea to the brain.
Vestibular system - senses linear and angular acceleration
Details of the vestibular system
3 semi-circular canals - sense angular acceleration (Yaw, Pitch, Roll)
Otoliths - made of 2 parts
- utricle
- saccule
Linear acceleration - > 0.1m/s squared
Part of the brain which processes balance
Cerebellum - processes data from the vestibular system
Audible range
20Hz to 20,000Hz
Most sensitive audible range
750Hz to 4000Hz
Describe Noise induced Hearing loss and what effects the severity?
Temporary loss of hearing due to an extended exposure to 90Db or more.
Temporary damage to the membrane of the cochlear.
Severity is effected by
- Intensity
- length of exposure
- Frequency (Hz)
Important Db levels to know
120Db - discomfort in the ear
140Db - Very Painful
160Db - ruptured ear drum (tympanic membrane)
Conductive Hearing loss
Failure of the conductive parts of the ear:
- Ossicles (3 bones)
- Ear Drum (tympanic membrane)
Caused by:
- Trauma
- Cold / infection
Presbycusis Hearing loss
Loss of hearing with Age.
High pitch sounds are the first to go.
Tinnitus
Constant form of sound in the ear.
In extreme cases causes people to go mad.
