Kap 4 - The nervous system, Ear, Hearing and balance

Question 1

Three distinct sections of the human ear?

Answer 1

The outer ear - AIR

The middle ear - AIR

The inner ear - LIQUID

Question 2

Pinna is?

Answer 2

Visible part of the ear

Question 3

Ear Canal do?

Answer 3

Channels the sound waves to the ear drum

Question 4

Ear Drum (tympanic membrane) is?

Answer 4

Separates the outer and middle ear, sound waves make the ear drum vibrate

Question 5

Ossicles. Consist of 3 Bones in the middle ear, name them:

Answer 5

Bones: (smallest bones in the body)

• Malleus (hammer)
• Incus (Anvil)
• Stapes (stirrup)

The 3 bones pick up vibrations from the ear drum and pass them to the inner ear

Question 6

The Vestibular System is?

Answer 6

Semi-circular canals measuring angular accelerations; Yaw, Pitch and Roll (can lead to illusions)

Otoliths:
Made up of; Utricle and Saccule

They sense linear accelerations

Question 7

Cochlea is?

Answer 7

(Snail)

Filled with fluid.

Vibrations in the cochlea are received through either the outer/middle ear or the skull by skull conduction

Question 8

Auditory Nerve is?

Answer 8

Information from the cochlea is detected by the auditory nerve, which leads directly to the cortex of the brain

Question 9

Eustachian tube?

Answer 9

Connected to passage of nose and throat and equalises pressure between the outer (atmospheric) pressure and the inner ear pressure.

Linked to otic barotrauma

Question 10

Audible range and measurement

Answer 10

Average adult human ear:
20Hz - 20,000Hz

Most sensitive to: 750-4000Hz (speaking tones)

Question 11

Noise Induced Hearing Loss. Max dB?

Answer 11

At 90dB - you can start to have noise induced hearing loss if exposed to for a while

• Temporary - caused by damage to the membrane of the cochlea
• How long depends on; Intensity, frequency, duration exposure
• If frequently exposed, it can lead to permanent loss of hearing

120dB - Discomfort in the ear

140dB - Painful

160dB - Rupture ear drum

Question 12

Conductive Hearing Loss

Answer 12

Conductive hearing loss is when the sound conducting elements of the ear are not working properly. Could be any of the following or a combination:

Cochlea
Auditory nerve
Ossicles
Excessive amounts of wax in the ear canal
Ruptured ear drums

Question 13

Name the parts of the middle Ear

Answer 13

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

Question 14

Name the parts of the inner Ear

Answer 14

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

Question 15

Important Db levels to know

Answer 15

120Db - discomfort in the ear

140Db - Very Painful

160Db - ruptured ear drum (tympanic membrane)

Question 16

Somatogravic Illusions

Answer 16

Linear acceleration illusion
Tilting head back = accelerate
Tilting head forward = deccelerate

Question 17

Somatogyral Illusions

Answer 17

Angular acceleration illusion

Habituation to a steady turn. When level again, impression of turning the other way.

Question 18

Spatial Disorientation

Answer 18

False impression of attitude because of:
- IMC
- aerobatics
- head movements
70% visual reference used for spatial orientation

Question 19

Coriolis Spatial Disorientation

Answer 19

+3 degrees

Question 20

What do we call the nervous system?

Answer 20

Electrical-chemical communications network!

Question 21

Central nervous system (CNS)

Answer 21

Responsile for issuing nerve impulses and analysing sensory date.

Question 22

Peripheral nervous system(PNS)

Answer 22

The PNS is made up of a series of specielies cells that both pass information and received from the body organs and muscles back tot eh CNS through sensory nerves.

Question 23

Autonomic (vegatative nervous system (ANS)

Answer 23

A special autonomic nervous system which manage stuff “automatic”. Like breathing, sweating, GAS.(fight or flight)

Question 24

The ear purpose?

Answer 24

Vibrations in the ear(sounds) and secondly balance organ and acceleration detector.

Question 25

Semicircular canal detect angular accelerations greater than?

Answer 25

0.5 m/s^2

Question 26

Cerebellum is?

Answer 26

Part of the brain which processes balance - processes data from the vestibular system.
(Dette er f.eks cerebellum der automatisk forberede dig på, inden du stiller dig på en rulletrappe, at tilpasse balancen således at du ikke falder når du går på).

Question 27

Otoliths?

Answer 27

Detect tilting of the head and linar acceleration

Question 28

Otoliths acceleration greater than?

Answer 28

0.1 m/s^2 causes the hair cells to bend.

Question 29

Spartial disorientation contributes to how many % of accident in:
General aviation?
Commercial transport operations?

Answer 29

37%

12%

Question 30

Symptoms of motion sickness

Answer 30

Nausea
Hyperventilation
Vomiting
Pallor
Cold sweating
Headache
depression

Question 31

Coriois effect need to be greater than how many degrees?

Answer 31

3Degrees a second

Question 32

Aircraft accelerates, what do the otoliths indicate to the brain?

Answer 32

That the aircraft is pitchin up, this feeling will be reinforced by an air driven artifical horizon

Question 33

What causes conductive deatness

Answer 33

Damage to the ossicles or the eardrum

Question 34

Lens happen in?

Answer 34

All flight conditions

Question 35

What detects accelerations and decelerations

Answer 35

The otoliths in the saccules canals

Question 36

Decibels increase

Answer 36

Linearly

Question 37

The vestibular apparatus detects ………. acceleration

Answer 37

Linear