Human Phys 6.5 Flashcards
What is pressure a result of?
Multiple impacts of moving molecules against a surface
What is pressure directly proportional to?
Concentration of the gas molecules
What is the partial pressure of gas equal to?
The fraction of that gas in the gas mixture multiplied by atmospheric pressure
What must the sum of all individual gas fractions equal?
One
What must the sum of partial pressures equal?
The total pressure
What happens when gas is dissolved in a fluid?
Solubility of the gas in the fluid contributes to the partial pressure and concentration of that gas
What happens when molecules are strongly attracted to each other?
They can not move as freely
Less impact against the surface
Less pressure generated
What happens to the partial pressure when molecules are strongly attracted to eachother?
Low partial pressure with more dissolved molecules
What happens to the partial pressure when molecules are repelled from eachother?
High partial pressure with less dissolved molecules
Henry’s law
Partial pressure= concentration of dissolved gas/ solubility coefficient
What is the solubility of CO2 compared to O2?
20x more
What is the main limitation of diffusion for gases?
Water not membranes (they are lipid soluble so they can move through membranes)
What are factors that affect rate of diffusion?
Diffusion coefficient of each gas
Surface area of the membrane
Partial pressure difference
Thickness of membrane
What is diffusing capacity of the respiratory membrane?
Volume of gas that will diffuse through the membrane each minute for a partial pressure difference of 1 mmHg
What is the diffusing capacity of O2?
21 (can increase to 65 during exercise)
