the ear, hearing & balance

Question 1

outer ear

Answer 1

pinna- visible part, funnel

ear canal

Question 2

middle ear

Answer 2

ear drum- sound waves to vibrations

ossicles- 3 types: malleus(hammer), incas(anvil|), stapes(stirup)

Question 3

inner ear

Answer 3

cochlea- vibrations into electrical signals, filled with liquid, wider part senses higher pitches
auditory nerve- transports electrical signal to brain
eustation tube- brings in air from nose

Question 4

average hearing frequency

Answer 4

20-20000Hz

Question 5

decibels

Answer 5

measurement of intensity of noise

Question 6

noise induced hearing loss (NIHL)

Answer 6

temporary
depends on intensity, frequency and duration of exposure 
over exposure to 8hrs+ at >85-90dB
sudden exposure to >120dB
could even burst ear drums

Question 7

conductive hearing loss

Answer 7

hearing works on conduction
can be blocked: wax, ear infection, hole in ear drums, damaged cochlea 
temporary 
perforation
clear wax with drops

Question 8

presbycusis

Answer 8

gradual hearing loss with age

higher tones affected more/ first

Question 9

3 sources for balance

Answer 9

proprioceptive system
visual system
vestibular system

Question 10

vestibular system

Answer 10

inner ear
filled with liquid
2 parts: semicircular canals & otolith

Question 11

vestibular system: semicircular canals

Answer 11

3 canals at right angles to each other (orthogonal)
measure angular accelerations(roll, yaw, pitch)
small hairs detect movement and convert to electrical impulses which are sent to vestibular nerve

Question 12

vestibular system: otolith

Answer 12

uricle and saccule
measure linear acceleration 
uricle measures horizontal acceleration 
saccule measure vertical acceleration 
also liquid filled
has hairs with chalk on the end(ear rocks) that convert movement to electrical impulses that are sent to vestibular nerve

Question 13

cerebellum

Answer 13

area of the brain for balance