Hf Flashcards
Learn hf biiiiitch (91 cards)
1
Q
What is one of the initial symptoms of hypoxia?
A
Impaired judgement
2
Q
First action that should be taken in event of cabin decompression above 10000ft?
A
Don o2 masks, check o2 flow
3
Q
Purpose of eustachian tube?
A
To equalise pressure on both sides of ear drum
4
Q
Vestibular apparatus detects ….. acceleration?
A
Angular and linear
5
Q
Dark adaptation takes how long for rods? Cones?
A
Rods 30 minutes. Cones 7 minutes
6
Q
At what altitude is partial pressure of o2 approx half that at sea level?
A
9000 ft
7
Q
At what altitude is atmosphere approximately half that at sea level? Quarter?
A
Half 18000 ft
Quarter 37400 ft
8
Q
Sea level pressure?
Sea level o2 partial pressure?
O2 partial inside lungs?
A
Sea level: 760mm Hg
Sea level o2 partial pressure: 159mmHg
O2 partial inside lungs 102 mmHg
9
Q
At what altitude does hypoxia set in?
A
8-10000 ft
10
Q
Standard atmosphere pressure?
A
1013.2 hPa
11
Q
Define hypoxia
A
Hypoxia is the deficiency of O2 reaching tissue cells
12
Q
What are the three major parts of the respiratory system?
A
Airway, lungs and the muscles if respiration.
13
Q
State anatomy and physiology of the airway.
A
Airway includes mouth, nose, pharynx, larynx, trachea, bronchi and bronchioles. Carries air between the lungs and body’s exterior.
14
Q
State physiology of the lungs.
A
Passes o2 into body and co2 out.
15
Q
State anatomy and physiology of the muscles of respiration.
A
Diaphragm, intercostal muscles. Work together as a pump.
16
Q
What is hypoxic hypoxia?
A
Decrease of o2 available. Results from high altitude.
17
Q
What are the symptoms of hypoxic hypoxia?
A
Euphoria Impaired judgement Headache Tingling in hands and feet Hyperventilation Muscular impairment Memory impairment (12000ft+) Tunnel vision Reduced night vision Impairment of consciousness Cyanosis Formication
18
Q
How can hypoxia be prevented?
A
Use of supplemental O2 Cabin pressurisation Decrease rate of ascent Time at altitude Alcohol/drug use Smoking Physical conditioning Nutrition Acclimation Use of automation
19
Q
What is the treatment for hypoxia?
A
Supplemental O2. Recovery is rapid.
20
Q
What is the O2 paradox?
A
Individual develops temporary increase in symptoms when being treated for hypoxia. May lose consciousness or develop fits for up to one minute.
21
Q
What the times of useful consciousness (moderate and minimal activity) for;
18000ft
25000ft
35000ft
A
18000ft 30/20 min
25000ft 3/2 min
35000ft 45/ 30 sec
22
Q
Define hyperventilation
A
Lung ventilation is excess of body’s needs and denotes overriding of normal control of breathing. Decreases carbonic acid level of blood
23
Q
What can cause hyperventilation?
A
Emotional; anxiety, fear, stress, panic attacks
Physical; exersise, hypoxia, cold shock, pain
Physiological; fever, infections, stroke, asiprin overdose, asthma, emphysema, hyperthyroidism, meningitis, metabolic acidosis.
24
Q
What are the symptoms of hyperventilation?
A
Drowsiness Light headedness Shortness of breath Headache Delayed reaction time Impaired judgement Euphoria Chest pain Numbness Tingling in extremities Unconsciousness
25
What is the treatment for hyperventilation?
Consciously slow breathing rate
Talk aloud/sing
Medication
Stess relief
26
What is the difference between hyperventilation and hypoxia?
Hypoxia is the state of insufficient o2 being delivered to the body whereas hyperventilation is excess lung ventilation required to remove CO2.
27
Define Barotrauma
Tissue damage resulting from strong pressure gradient between air filled cavities.
28
What causes barotrauma?
Results from inverse pressure/volume described in Boyles Law. Rapid drops in atmospheric pressure result in air filled cavities expanding.
29
What are the four main areas that contain trapped gas?
Behind eardrum
Middle ear
Sinuses
Stomach
30
What are the symptoms of barotrauma in following parts of the body?
Lungs - no pain
Ears - Severe pain, hearing loss, tinnitus, ear infections, bleeding ear and vertigo.
Sinuses - Excruciating pain in upper cheeks, above eyebrows and in upper teeth. Nosebleeds.
31
How can barotrauma be prevented?
Gradual rates of climb/descent
Pressure suit
Consciously equalise pressure. Hold noelse and blow.
Avoid flying w certain medical conditions
32
How can barotrauma be treated?
Hyperbaric O2 chamber
Medical treatment - decongestants, possible surgery.
Stop descent if barotrauma effects felt.
33
List the parts of the eye
Cornea, The Lens, Retina, Fovea, Optical Nerve, Cones, Rods, Iris
34
Describe anatomy physiology of the lens
Curved, flexible, transparent structure that focusses light onto retina. Controlled by cillery muscles.
35
Anatomy/physiology of retina
Multilayer sensory nerve cells. Contains rods and cones. Very sensitive it o2 deprivation
36
Physiology of cornea
Refracts light
| Protects eye
37
Physiology of fovea
Small pit in center of retina. Contains only cones. Gives sharp central vision (20 degrees) and acquity.
38
Physiology of optical nerve
Nerve that connects the eye to the brain. Carries electrical impulses formed by the retina to the brain
39
Physiology of Cones
Responsible for colour and detail. Concentrated in Fovea. Requires high light levels to function
40
Physiology of rods
Located in retina. Sensitive to low levels of light. Enable scotopic vision and responsible for peripheral vision. Grayscale only
41
Why does each eye have a blind spot?
It's where the optic nerve connects to the eye
42
What is empty field myopia?
A lack a visual queues causes the eye to return to it's resting focus of 1-2 meters in front of pilot. Regain long distance focus by constantly scanning. Eg wingtips
43
Describe autokineses
Stationary objects appear to move due to few visual queues. Often happens at night. To correct, shift your gaze or make eye/head/body movements.
44
What is flicker vertigo/ stroboscopic illumination? How to correct for it?
Propeller causes strobe effect which causes vertigo, disorientation, nausea, seizures. To correct, turn away from light source.
45
What is Break off Phenomena and how to correct for it?
Feeling of being outside cockpit. Happens at night at high altitude w few visual/mental/physical stimulae. To avoid, keep busy.
46
Describe sector whiteout and how to correct for it.
Visibility and contrast severely reduced. Horizon disappears completely. Gives feeling of descending/ ascending. No depth perception. Trust instruments
47
Describe Black Hole phenomena and how to correct for it
Happens when approaching runway among unlit terrain. Causes pilots to think they are higher than they are. To correct, use all visual queues available.
48
What is the effect of a sloping runway?
Upwards slope will appear longer and make pilot feel high. A downwards slope will make pilot feel low.
49
What is the effect of runway width to a pilot?
A wide runway will appear closer than it is. A narrow runway will appear further away
50
Describe anatomy/ physiology of circulatory system.
Heart - Pump. Divided into two sides each w two Chambers.
Blood vessels - form system of arteries, veins and capillaries.
Pulmonary system - diverts blood to lungs
Blood pressure - measure of blood against walls of main arteries.
51
Explain mechanical effect of partial pressure of O2 on oxygen transfer in lungs
Low partial pressure O2 will decrease oxygen transfer in lungs. 55mmHg or less hypoxia sets in
52
Define decompression sickness
When too rapid decompression causes nitrogen bubbles to form in tissue.
53
List symptoms of dcs
The bends - N bubbles in joints cause rheumatic pains
The creeps - N bubbles form under skin
The chokes - N bubbles get caught in lungs
The Staggers - N bubbles effect blood flow to brain causing loss of mental function/movement control
Secondary Symptom - Post descent collapse. When N bubbles reach heart
54
How to prevent dcs?
By use of O2 before high altitudes
55
Wxplain dangers of flying after diving
Strong pressures felt during diving resulting in N being absorbed into tissue. Flying releases N bubbles
56
Distinguish rod and cones function/distribution in retina
Cones responsible for colour n detail. Concentrated in Fovea.
Rods responsible for scotopic and peripheral vision. Grayscale only. Found in retina
57
Describe conditions leading to false horizon
Overcast, between cloud layers, snow w cloud above, low or mountain flying w obstructions between pilot and horizon
58
Explain relative motion
False impression of movement relative to surroundings. What thinking you're moving forward when car next to you is going backwards
59
Explain effect of sloping terrain on visual perception
Can give false horizon. Gives false vertical so pilot thinks they are decsendibg or ascending
60
How can bright approach lights affect pilot?
Depth perception
61
Describe suitable sunglasses for aviation
100% UV protection
Non polarised due to interaction with displays
Thin frames
62
What is the 'see and avoid' method?
Method for avoiding collision requiring pilots to actively searching for and avoid traffic.
Effective visual scanning and information gathering from radio
63
Explain use of visual cues during landing
Maintain glidescope primarily by runway and terrain
64
Describe basic anatomy/physiology of the ear
External ear
Pinna - receives sound waves
Ear canal - acts as funnel
Middle Ear
Ossicles - hammer, anvil, stirrup. Amplify sound
Eardrum/ tympanic membrane - cone shaped skin, vibrates, separates outer ear from middle
Eustachian Tubes - connects middle ear to back of nose. Equalises pressure.
Inner ear
Cochlea - spiral tube covered in stiff membrane and thousands of hairs. Converts mechanical energy to electrical energy and sends to brain via auditory nerve.
Vestibular Apparatus - regulates balance, 3 semi circular canals that determine movement. Hair cells I each canal send information to brain
Otolithic Organ - co-located but separate from vestibular apparatus. Stimulates hair cells to give sense of equilibrium.
65
Explain effects of prolonged noise exposure on hearing
Temporary hearing loss
80db+ can lead to permanent damage
130db can cause damage to hearing, ossicles and eardrum
66
Explain effects of presbycusis
Speech of others mumbled or slurred
High pitched sounds hard to hear
Men's voices easier than women'
Tinnitus maybe
67
Explain effects of pressure changes on middle ear and eustachian tubes
Pain in ear
| Muffled hearing
68
Define spatial orientation
Our natural ability to maintain body orientation and posture in relation to surrounding environment
69
Explain connection between visual and kinasthetic senses in maintaining balance
Visual senses far better than kinasthetic
| If kinasthetic and visual sense different, kinasthetic senses will be ignored
70
Explain body's limitations in maintaining spatial orientation when vision adversly affected
Kinasthetic senses can't be relied on to maintain spatial orientation.
71
Explain effects of The leans/ subthreshold stimulation
Fluid in semi circular canals catches up and stops stimulating hair cells causing perceived straight and level flight
72
What is the somatogravic illusion
When the brain confuses de/acceleration for pitching up/down
73
What is cross coupled turning (coriollis effect)
Simultaneously trigger two semi circular canals eg my moving head up/down while aircraft is rolling. Results in disorientation - vertigo
74
What is pressure vertigo
A form of veritgo triggered by collapse of eardrums caused by blocked eustachian tubes. Can happen when flying with cold or blocked sinuses.
75
The balance organs in the inner ear are...?
The main organs for spatial orientation
76
Pilots buying over the counter medication may..
Experience side effects while taking the medication, that means the medication is unsuitable for flying
77
When flying, to maintain spatial orientation:
All three orientation systems are used but can give conflicting information to the brain
78
How much do trapped gases in the body expand at 7000ft?
40%
79
Medication should always be
Ground trialled for a few days before flying is planned
80
When approaching a shorter runway, pilots will sometimes tend to fly an approach which is too?
Steep
81
A pilot who has been drinking heavily should:
Wait for a minimum of twice the time it takes for all the alcohol to leave their body before flying
82
Some symptoms of hyperventilation are:
Light headedness, tingling and numbness
83
The bends if not treated can..
Lead to unconscious and death
84
For flying or scuba diving, the bends needs to be treated in a
Recompression chamber
85
What is the minimum time between drinking and flying?
10 hours
86
What us the occulogyral reflex?
Interconnection between the eyes and balance organs which allows visual tracking of objects when head and body are moving
87
What are the three main body systems involved with orientation
Vision, balance organs in ear and nerve system sensors
88
What does the otolith organs sense?
Head/body tilt and linear acceleration
89
What orientation illusion can occur when a pilot has been in a constant rate if turn for too long? Why?
The keans. Because the fluid in the semi circular canals no longer register any change
90
What runway factors nay cause a pilot to make an approach that is too low? Too high?
Low
Long runways
Uphill runways
High
Short runways
Downhill runways
91
Explain the rules and dangers of flying after diving
Less than 10m dive - no flying for 12 hours
Greater than 10m - no flying 24 hours
Greater than 35m -no flying for 48 hours
Dangerous because divers experience greater than 1 atmosphere ambient pressure which forces nitrogen into tissue. When flying after diving, less than 1 atmosphere ambient pressure means the absorbed nitrogen is released into blood
