Intro To Altitude Physiology Flashcards
Describe the structure atmosphere
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
Describe the composition of atm
- Oxygen 21%
- Nitrogen 78%
- Other gases
— argon
—CO2
—Water vapour
Function of Atmosphere
Radiation protection from ionising and ultraviolet. Eg layers of ATM and Ozone .
Thermal protection - natural greenhouse effect.
Support of life - Oxygen is being key.
Dalton’s law
Total pressure of a mixture of gases is equal to the sum of the partial pressure of each of the constituent gases.
Measurement of Pressure
MSL = 760mmHg = 1013.2hPa = 1bar = 14.7 psi
Lapse rate of temp in altitude
1.98 degree/1000ft up to 36089ft
% of Atm at different altitudes
Exponential decrease of pressure with increasing altitude. At 18000ft = 50% atm 25000ft = 33% atm 35000ft = 25% atm 55000ft = 10% atm
Armstrong’s limit
63000ft
Atm pressure = 47mmHg
Boiling point of water vapour
Body boils
Characterise the risk of radiation exposure for aircrew given different condition of latitude and altitude
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
Describe the different zones
MSL - 10000ft =. Physiology Zone
10000-50000ft = Physiologiical deficient zone
> 50000ft = space equivalent zone
Boyle’s law
At constant temperature pressure is inversely proportional to volume
Henry’s law
Constant temp, amount of gas dissolves is directly proportional to partial pressure of the gas
Gay- Lussac’s law
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.
Charles’ law
Volume is directly proportional to its absolute temperature at constant pressure.
Combined gas law
(P1V1)/T1=(P2V2)/T2