Chapter 7 - The Ear Flashcards
What is in the Outer Ear
Pinna and Auditory canal
What is in the Middle Ear
Ear drum / Tympanic membrane Ossicles x3 Bones called Hammer/malleus Anvil/Incus Stirrup/Staples
What brings pressure up to balance each side of the ear drum
Eustachian Tube
What is in the Inner Ear
Cochlea - filled with fluid and when struck against by the stirrup will send electrical signal to the brain via Auditory nerve
What can the ear hear and what is the most annoying sounds
20-20,000 hz
intermitted high pitch
Noise induced hearing loss is usually temp or long term?
temp
What Db cause Noise induced hearing loss
80-90db continuous for 8 hours + or
sudden 120 db
What are the x3 factors involved with hearing loss
frequency
duration
intensity
Conductive hearing loss is usually?
Permanent
Causes x4 are
Damaged Ossicles
Damaged Cochlea
Excessive amount of wax
ruptured ear drum
Presbycusis is?
Loss of hearing because of age
Vestibular system is made up of
3 semi circular canals to sense pitch, roll and yaw
filled with liquid
The vesicular system has two chambers called and used for which axis
Utricle - left, right, forward, back
Saccule - up/down
The x3 semi circular canals detect?
Angular acceleration
The utricle and saccule detect?
Linear acceleration
Both travel up the vestibular nerve to the?
Cerebellum
What are the vestibular illusions
That it only detects initial movement
only detects movement if the stimuli meets the sensory threshold
Assumes all linear acceleration through the body is gravity
What is somatogravic illusion
Acceleration gives the illusion of pitch up
Deceleration gives the illusion of pitch down
What is grave yard spin
When you think you’ve recovered a spin but you re-enter it
what is spatial disorientation
When you have false perception of orientation of the aircraft with respect to spacial references - like flying in IFR
Percent of Spatial Disorientation crashes are fatal?
80%
Coriolis is
When we simultaneously stimulate two or more semi circles at the same time
Vertigo is
Contradictory information is sent to the central system causes Neusa
What does alcohol do the ear
lowers the specific gravity of liquid in the cochleas
Counters against disorientation
Minimise head movements
check instruments regularly
What is the somatogyral illusion
long gentle turns
prolonged
when straight and level you believe you are banking the other way
