Session 7 Physical Principles of Gas Exchange Flashcards
Room air gasses and percentages
Oxygen 21%
Nitrogen 79%
What type of energy provides the source for the diffusion process
Kinetic Energy
Movement of gas in one direction is the effect of…
concentration gradient
Rate of diffusion is dependent on _________.
pressure
total pressure commonly used
1 atmosphere (weight of a column of air a mile high) 760 mmHg
The colder the liquid the ________ gas it can absorb.
more
Henry’s Law
solubility of a gas in a liquid depends on temperature, the partial pressure of the gas over the liquid, the nature of the solvent, and the nature of the gas.
Carbon dioxide is ____________more soluble than oxygen.
20 times
Rate of net diffusion os determined by
difference of partial pressures (pp)
If pp of gas in alveoli > blood then gas moves into ________.
blood
oxygen
If pp of gas in blood > alveoli then gas moves into
alveoli
Carbon Dioxide
Partial pressure of water escaping surface into gas phase = vapor pressure. Vapor pressure is _______ when a gas mixture is fully humidified at 37degrees C
47 mmHg
With vapor pressure considered, what is the remaining total pressure of gases in the air?
713 mmHg
760 mmHg - 47 mmHg (vapor pressure)
What factors affect gas diffusion rates in fluids?
Pressure differences Gas solubility in fluid area of fluid distance which gas must diffuse molecular weight of gas Temperature of fluid (constant in body)
D is directly proportional to
solubility
D is inversely proportional to
the square root of the gas’ molecular weight
Rate of gas movement into tissues is limited by diffusion rate of gas through _________.
tissue water