The nervous system Ear and Hearing Balance. Aerodoc

Transcription

1 The nervous system Ear and Hearing Balance

2 The nervous system Central Nervous System (CNS) - The Brain (1,4 kg) - The spinal cord Peripheral Nervous System (PNS) - Sensory nerves - Motor nerves Autonomic Nervous System (ANS) s. 4-14

3 The Brain s. 4-14

4 Cerebral cortex with the location of function s. 4-14

5 The tactile sense in brain Homunculus

6 How to make a movement

7 Electrical stimulation of brain tissue can produce movement and experience Wow! Den var god. Prøv v den, Rasmussen - pirk ved den vinding, hvor jeg holder fingeren Gade

8 The Brain and The spinal cord s. 4-14

9 The peripheral nervous system (PNS) s. 4-14

10 The autonomic Nervous System (ANS) Breathing Blood pressure Temperature Sweating Gastrointestinal motions Urinary output Fight or Flight Response (GAS) s. 4-24

11 The nerve cells (neurons) and synapsis s. 4-14

12 THE SENSE ORGANS In aviation the most important sense organs is: EYE EAR s. 4-24

13 The ear 2 functions: - receive sounds - balance organ s. 4-24

14 The ear Ear ossicles Semi-circular canals Sound waves Cochlea Ear drum Eustachian tube s. 4-34

15 The ear Important because: Incidence of sudden incapacitation: 35-40% are related to the ear - sinus / middle ear barotrauma - vertigo - nausea - bleeding from nose 60% of other cause

16 Trapped Air As you go up in altitude, air expands... if this air is trapped, expanding air can lead to pain. A blocked Eustachian tube could lead to pain in the middle ear. Ear Drum Eustachian Tube

17 Sinus Blocks and Ear Blocks There are spaces in the sinuses and middle ear where air can get trapped. Under normal conditions this air can escape through passages to the outside FRONTAL ETHMOIDS SPHENOIDS MAXILLARY

18 The sinus

19 tur gennem øret.lnk

20 Displacement depending of -Frequency -Intensity

21 Normal hearing Frequency Hz with intensity below 20 decibels s. 4-44

22 Hearing Impairment Conductive deafness (wax, damage to the ear drum, damage to the small bones) Noise induced Hearing Loss (NIHL) Presbycusis s. 4-54

23 Noise Induced Hearing Loss (NIHL) When exposed to loud noises in excess of 90 db In aviation: piston engine aircraft (120 db) jet aircraft (130 db, threshold of pain) helicopter Use hearing protection to noise in excess of 115 db (normal speech cannot be clearly heard at 2 metres)

24 Take care of your hearing

25 Audiogram Decreased understanding Deafness

26 Consequence of hearing loss Difficult hearing weak speech (loss of sensitiveness) Better speech understanding Difficult hearing consonant (loss of high frequency) Be er ee under anding Difficult understanding speech in noisy environment (loss of attention) Be er ee under anding

27 The sense of spatial orientation

28 Orientation sense

29

30 The inner ear s. 4-64

31 The vestibular apparatus Semi-circular Canals (angular movements) Otoliths (linear movements) s. 4-64

32 Anatomy of Semi-circular Canal s. 4-64

33 Orientation in space of the Semi- circular Canals and Otoliths s. 4-64

34 Semi-circular Canals in relation to aircraft movements s. 4-64

35 Sensitivity of vestibular apparatus Semi-circular canals: x-axe: 3 o /sec 2 for roll y-axe: 7 o /sec 2 for climb 4 o /sec 2 for dive z-axe: 2 o /sec 2 Otolith organ: x-axe 0,1 m/sec 2 z-axe 0,1 m/sec 2

36 Movement of fluid in Semi-circular Canal in response to head movement s. 4-74

37 Sensation of movement after stop of head movement s. 4-74

38 The vestibular apparatus Semi-circular Canals (angular movements) Otoliths (linear movements)

39 Otoliths (saccules + utricles) s. 4-64

40 Function of otoliths (no movement) s. 4-64

41 Function of otoliths (head down/up) s. 4-64

42 SPATIAL DISORIENTATION Contributory factor in 37% of accidents in general aviation (12% commercial) 80% of disorientations accidents are fatal s. 4-74

43 Spatial Disorientation VISION VESTIBULAR SEAT-OF-THE-PANTS s SENSES OF BALANCE ORIENTATION AND BODY RESPONSES

44 Spatial Disorientation Oculogyral Illusion Oculogravic Illusion VISION VESTIBULAR SEAT-OF-THE-PANTS s SENSES OF BALANCE ORIENTATION AND BODY RESPONSES

45 Spatial Disorientation Somatogravic Somatogravic VISION VESTIBULAR SEAT-OF-THE-PANTS s SENSES OF BALANCE ORIENTATION AND BODY RESPONSES

46 Spatial Disorientation VISION VESTIBULAR SEAT-OF-THE-PANTS s SENSES OF BALANCE ORIENTATION AND BODY RESPONSES

47 Seat of the pants s. 4-64

48 Spatial disorientation Somatogyral Illusion (Semi-circular Canals) Leans The Graveyard Spin Coriolis effect Oculogyral Illusion (Semi-circular Canals) Nystagmus Somatogravic Illusion (Otolith( Organ) Oculogravic Illusion (Otolith( Organ)

49 Leans s. 4-74

50 False sensation from semi-circular canals s. 4-84

51 Somatogyric illusion s. 4-94

52 The Graveyard spin If IMC: BELIEVE YOUR INSTRUMENTS If VMC: LOOK OUT AT THE HORIZON s. 4-84

53 Coriolis Effect s

54 s

55 Coriolis Effect s

56 Somatogravic illusion 1 s. 4-64

57 Oculogravic illusion

58 Preventive advise

59

60 Spatial Disorientation during flight = Definition: Vertigo Any event appearing during flight, where the pilot experience a false percept of his own position, attitude or motion relative to the earth's surface s. 4-94

61 Vertigo (ex) Alternobar vertigo Sudden pressure changes in the inner ear (note: strong blowing of the nose + Valsalva) Accelerations or high G loadings Drug-induced Alcohol-induced s. 4-94

62 Alcohol before flying, a ticking time-bomb... Simply relying on hangover effects like a headache is not sufficient to determine if you should not be flying. s

63 Alcohol and nystagmus s

64 So how long does it take to clear your endolymphatic fluid of alcohol? 24 hours 36 hours 8 hours 12 hours 48 hours

65 The British Authorities After drinking alcohol: wait hours before flying or hours/unit

66 Motion Sickness Neuronal mismatch between the visual and vestibular signals. s

67 BUILDING THE PERFECT ORIENTATION DEVICE Components of the Vestibular System Vision Auditory VESTIBULAR SYSTEM Vestibular Apparatus Proprioceptive

68 DON T FORGET THE COCONUT INPUT Cortical Vision VESTIBULAR SYSTEM Vestibular Apparatus Auditory Proprioceptive

69 When Components Disagree... Cortical Vision VESTIBULAR SYSTEM Vestibular Apparatus Auditory Proprioceptive Vomiting Center

70 Engage your coconut! SO WHAT CAN WE DO? Vision Cortical Open your eyes, look out Keep your head still VESTIBULAR SYSTEM Vestibular Apparatus Auditory Turn up the volume Put your foot on the floor! Proprioceptive Nausea, Vomiting, Cold sweating ect.

71 Medication! Only after consult to a flight doctor and never to use on flightdeck