Physiology: Rate of gas exchange across alveolar membrane Flashcards
what are the 4 factors that influence the rate of gas exchange across the alveolar membrane
partial pressure gradient of O2 and CO2
diffusion coeffecient for O2 and CO2
surface area of alveolar membrane
thickness of alveolar membrane
what is Daltons Law of partial pressures
The total pressure exerted by a gaseous mixture = the sum of the partial pressures of each individual component in the gas mixture
what does partial pressure of a gas determine
the pressure gradient for that gas
what is the partial pressure of a gas
the pressure that one gas in a mixture of gases would exert if it were the only gas in the whole volume occupied by the mixture
(at constant temp.)
describe how gases move by partial pressure gradient
they move from higher partial pressure to lower partial pressure
what is the diffusion coefficient of a gas
the solubility of that gas in membranes
why is the partial pressure gradient for CO2 much smaller than that for O2
because CO2 is more soluble(20 times) in membrane than O2
what is Ficks law of diffusion
amount of gas that moves across a membrane in unit time is proportional to the area of tissue BUT inversely proportional to its thickness
describe the factors that would increase rate of gas transfer(4)
increase surface area
decrease membrane thickness
increase diffusion coefficient
increase partial pressures
