Intro To Altitude Physiology Flashcards

1
Q

Describe the structure atmosphere

A
Troposphere - <58000ft
- cold to the tropopause
Stratosphere - 58-158000Ft
- contains Ozone layer
- warms up to stratopause
Mesosphere - 158 - 290000ft
- cold until the mesopause
Thermosphere - 290-700000ft
- warms up again
Exosphere >700000ft
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2
Q

Describe the composition of atm

A
  • Oxygen 21%
  • Nitrogen 78%
  • Other gases
    — argon
    —CO2
    —Water vapour
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3
Q

Function of Atmosphere

A

Radiation protection from ionising and ultraviolet. Eg layers of ATM and Ozone .
Thermal protection - natural greenhouse effect.
Support of life - Oxygen is being key.

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4
Q

Dalton’s law

A

Total pressure of a mixture of gases is equal to the sum of the partial pressure of each of the constituent gases.

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5
Q

Measurement of Pressure

A

MSL = 760mmHg = 1013.2hPa = 1bar = 14.7 psi

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6
Q

Lapse rate of temp in altitude

A

1.98 degree/1000ft up to 36089ft

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7
Q

% of Atm at different altitudes

A
Exponential decrease of pressure with increasing altitude.
At 18000ft = 50% atm
25000ft = 33% atm
35000ft = 25% atm
55000ft = 10% atm
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8
Q

Armstrong’s limit

A

63000ft
Atm pressure = 47mmHg
Boiling point of water vapour
Body boils

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9
Q

Characterise the risk of radiation exposure for aircrew given different condition of latitude and altitude

A

Higher = more particular
Galactic and solar
Protons, alpha particles and heavy nuclei, gamma
Secondary radiation from collision with ATM and aircraft
Depends of location eg magnetic fields
Average aircrew dose 3-4mSv per year
Occupation limit 20mSv per year

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10
Q

Describe the different zones

A

MSL - 10000ft =. Physiology Zone

10000-50000ft = Physiologiical deficient zone

> 50000ft = space equivalent zone

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11
Q

Boyle’s law

A

At constant temperature pressure is inversely proportional to volume

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12
Q

Henry’s law

A

Constant temp, amount of gas dissolves is directly proportional to partial pressure of the gas

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13
Q

Gay- Lussac’s law

A

states that the pressure of a given mass of gas varies directly with the absolute temperature of the gas, when the volume is kept constant.

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14
Q

Charles’ law

A

Volume is directly proportional to its absolute temperature at constant pressure.

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15
Q

Combined gas law

A

(P1V1)/T1=(P2V2)/T2

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16
Q

Pascal’s principle

A

Pressure applied to an incompressible liquid will be transmitted equally throughout the liquid

17
Q

Fick’s law

A

Vgas = (A/T) D (P1-P2)

A surface area
D = Solubility/square root of molecular weight

18
Q

What are the aeromedical relevant laws

A

Boyle’s law
Dalton’s law
Henry’’s law
Graham Law

19
Q

Graham’s Law

A

Rate of effusion of a gas in inversely proportional to the square root of the mass of its particles.

20
Q

Explain how the gas law’s affect physiology at Altitude.

A

.