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Flashcards in Basics of Flight Physiology Deck (62):
1

State the units used when measuring the total and partial pressure in atmosphere

Pascals or N/m2

2

State proportions and pressures of O2, N and other in atmosphere

78%,21%,1%

Partial pressures are in same proportion as the volumes. Total pressure is 760 mm Hg, so

Nitrogen 0.78*760=592.9 mm Hg
Oxygen 0.21*760=160 mmHg

3

What happens to proportions of gases throughout the atmosphere

They are constant

4

What is Boyles Law?

P and V are inversely proportional

Barotrauma

5

Charles's Law

V is proportional to T

6

Gay-Lussac

T proportional to P

7

What is the combined gas law/ general gas law

PV/T = const

8

Daltons

Sum of partial pressures in mixture is equal to total pressure

This causes Hypoxia

9

Henry's Law

Amount of gas dissolved in liquid is proportional to its partial pressure

This is to do with Decompression sickness

10

What are ICAO parameters?

What is standard temperature lapse rate?

T = +15degC
P =1013.25 hPa or 760 mmHg or 29.92 inHg
RHO = 1.225kg/m3

Lapse rate is -1.98degC per 1000ft

11

State altitudes that the pressure will be at percentages of MSL pressure

75% - 9000ft
50% - 18000ft
25% - 34000ft

12

State effects of increasing altitude on overall pressure and partial pressures?

Pressures will decrease but partial pressure ratios will remain constant

13

Ficks law

Mathematically shows diffusion rates

14

Explain differences in gas expansion between alveolar and ambient air when climbing

More CO2 and water vapour in lungs than outside.

Air is constantly saturated at 37degC

Lung air pressure is always reduced by 47mmHg in lungs

So at MSL air pressure in lungs is 760mmHg-47mmHg=713mmHg

The effect of this constant reduction becomes disproportionally large at higher altitudes.


The proportions of others gases must fall. At 34000ft, oxygen is 13.7%

15

What conditions do humans need to survive at given altitudes?

Up to 10000ft - nothing
to 33700 ft - 02 + air mask keeps body at MSL
up to 40000ft - 100% oxygen in mask keeps body at 10000ft
above - pressurised oxygen

16

What is the importance of partial pressure

Lungs hold less % of oxygen at altitude due to partial pressure of water vapour, and decompression sickness happens due to dissolving of Nitrogen

17

List the main components of the respiratory system and their function

Nose - warms air
Trachea - brings air to lungs
Bronchi - splits into two lungs
bronchioles - sub-branches
Alveoli - surrounded by capillaires. diffuse o2 into blood
Diaphram - muscles that control breathing
inter-costal muscles - does heavy breathing

18

What are the different volumes of air in the lungs.

Tidal volume - Normal breath - 500ml
Inspiratory res volume - additional to fill lungs - 3100ml
Expiratory res volume - air that can be forcibly expired - 1200ml
residual vol - what is left 1200ml

Max air that can fill lungs = sum of all=6000ml


Vital capacity = Total that can be expired = 6000-1200 = 4800ml = 80% of total

Inspiratory capacity = max that can be inspired = 3600ml



19

What is the normal respiratory rate?

About 12-20/min

20

How are oxygen and carbon dioxide transported around the body?

What effect do they have on acidity

Oxyhaemoglobin and Co2 in blood.

High -> low pressure across alveoli

More oxygen in blood - more alkaline
More CO2 in blood - more acid

Heavy breathing for no reason = more oxygen so more alkaline

21

Explain the role of carbon dioxide in control and regulation of respiration

Blood is very efficient at holding onto oxygen, so its nearly always at 98%.

Carbon dioxide goes up and down so this is measures and breaths taken accordingly

22

How is oxygen transferred to the cells?

Through tiny capillaries

23

What is external and internal respiration

External is in lungs, oxygen and CO2 transfer

Internal is O2 and Glucose at the tissues
02 and glucose emtabolised to form fuesl for the muscles

Waste is carbon dioxide and water

These combine to form carbonic acid. This controls rate of breathing.

Waste water goes through sweat, kidneys or lungs

24

List the different senses

Touch taste smell hearing sight

25

State the multi-sensory nature of the human perception

Use all the sense together

26

Name the main parts of the central nervous system

brain, spinal cord

27

State basic functions of central nervous system

Most information processing
Voluntary movements
Receiving info from senses
thinking
memory
emotion

Lower functions such as breathing and basic motor functions such as posture are closely associated with the brain stem

28

State basic functions of peripheral nervous system

Somatic -
Body movement and sensing external stimuli

Autonomic -
Unconscious things like blood vessels and control of internal organs

Has sensory and motor nerves

29

Discuss broadly how info is processed by nervous system and the role of reflexes

Senses by sensory neurons as part of peripheral system. These go to central nervous system and an action is called upon. This is then passed to motor neurons if needed.

Sometimes there is a direct link via spinal cord for a reflex action

30

Discuss electro-chemical nature of nerve impulse

One cell is a neuron. Has a cell body and an axon.

Signal travels length of axon as electrical wave. Is a chemical-electrical process. Called action-potential.

This goes at 0.5m/sec

Long motor neurons need faster method. Small breaks in the axon allow the signal to jump between the gaps. This is much faster. 100m/sec

31

Define sensory threshold

Below this the neuron won't fire. For 5us after this the neuron requires much bigger stimuli to fire. This is habituation.

32

Define habituation and implication for flight safety

Decrease in physiological response as result of repeated stimuli.

Flight safety - don't process things you should.

33

What is the gap between neurons called?

Synapse

34

What do the proprioceptors and mechanoreceptors do?

Proprioceptors detect and relay very precise information about the length of extension of each muscle.

Mechanoreceptors transmit very precise information about the amount of tension in a muscle

35

What do subcutenous receptors do?

They detect pressure. They are under the skin.

36

What is the endocrine system?

Slower means of communication. But can reach more cells.

Uses hormones in the blood, detected by receptor cells.

This is neural hormonal.

Not remotely voluntary. It plays a big role in homeostasis.

Examples. Insulin and adrenaline

37

Describe action potential

Uses sodium and potassium. PD builds up causes current to flow

38

Define humidity and relative humidity

What volume of water vapour per unit volume of air?

Relative is the proportion of water in the air compared with what could be held for a given temperature.

39

Hypoxia - two types and explain

Hypoxic hypoxia - not enough oxygen in system.
Caused by altitude, infection of lungs or airways, astham, drugs

Anaemic hypoxia - Caused by lack of red blood cells or inability for blood to carry oxygen. Can be from blood disorders or blood donations

Hypoxia is an example of Dalton's Law - partial pressures

40

What are symptoms of hypoxia?

Initial - Stomach pain as gas expands, tingling sensation in hands and feet
Cyanosis - blue lips and feet
Increased rate of breathing
Euphoria - happy/calm
Ear discomfort

After symptoms
- Impaired vision
lack of motor skills
drowsy
slurred
memory loss
difficulty concentration

41

State why living tissues need oxygen

To combine with glucose to release energy

42

How high can healthy people compensate for lack of oxygen?

Up to 10000 - 12000 ft

43

How are altitudes broken down into how we deal with o2?

Indifferent 10kft Blood 02 is 95-90%
Compensatory 10-15kft 90-80%
Disturbance 15-20kft 80-70%
Critical 20-23kft 70-60%

44

What is time of useful conciousness?

Time available to fix your situation!

Times on wall

45

What happens above 10000 for hypoxia?

Indifferent up to 10000
10-15 - Compensatory stage, bosy adapts, may feel tired, may be difficult to do simple tasks
+15 Disturbance Visual, poor judgement
+20 Death

46

Factors affecting severity of hypoxia?

Smoking reduces TUC times by half

47

Define hyperventilation

Breathing faster than necessary, too much oxygen. Too alkaline.

Alkaline does damage. Brain slows blood flow to avoid damage.

48

Causes of hyperventilation

Factors that make it worse

Treatment

Voluntary
Stress/anxienty
strokes/brain injuries

Reduced air pressure
respiratory disorders
cardiovascular disease
g-force
heat

May be physiological or psycological

Bag breathing

49

Symptoms of hyperventilation

DIzzy
Tingling
Nausea
Blurred Vision
Muscle Spasms
Loss of consiousness

Not dissimilar from Hypoxia

Bad question - below 10000ft, Hyperventilation
above - Hypoxia

Otherwise always treat for hypoxia

50

What is decompression

To do with Henry's Law - amount dissolved is ppl to pressure

High Pressure to low pressure, Nitrogen is released into bubbles known as embolisms.

These get trapped in pinch points such as joints or organs, causing similar damage to a blood clot.

51

State altitudes to do with compression

To 14000 feet - no effec
Above 18000 - affect if prolonged
Above 25000 - affect is worsened

52

What are the 3 types of decompression sickness?

Bends - joints
Creeps - skin
Chokes - Large embolism in the heart. Chest discomfort them cough
Staggers - Brain

53

State diving limits with decompression sickness

Not fly within 12 hours of dive less than 30ft
Not fly within 24 hours of dive less more than 30ft

No risk with snorkelling

54

Treatments of decompression sickness

Always increase ambient pressure. So descend or use hypobaric chamber.

Need specialist medical attention for a long while afterwards

Can be limited with pre-oxygenation.

55

Name parts of circulatory system

Heart
Arteries
Veins
Capillaries

56

What are normal pulse, normal stroke rate and normal cardiac output

70 ml/ stroke * 72 BPM = 5.04L

57

Name four chambers of the heart and describe their function

Ventricles and Atria (Atrium of a building)

Left - Pumps to body
Right - pumps to heart

Atria stores it ready to go into ventricle
Ventricle does big push out of heart.

Stroke vol is the capacity of left ventricle

58

Describe arteries, veins, capillaries

Arteries - HP. thick
Veins - Thinner, has valves, deoxygenated blood
Capillaries - One cell thick

Pulmonary vein and artery are named the other way round

59

What do coronary arteries/veins do?

Supply blood to the heart muscle

60

Describe the main constituents of blood?

Red blood cells - carry oxygen
White blood cells - infection
Platelets - Coagulate blood/clotting
Plasma - transparent/yellow fluid. Has no cells. Just a liquid
Carbonic acid - Regulate breathing and pulse

61

What is the affect of altitude on haemoglobin - oxyen saturation

Not sure yet

62

List factors that determine pulse rate

70-75 BPM
Controlled by autonomic or vegetative nervous system

ANS monitors - carbonic acid
glucose
adrenaline
exercise
digestive
temp up BPM up
increases with age
blodd pressure down rate up
caffeine
woman high than man