Lec 26 Flashcards
air is composition of
78% N2
21% O2
0.033% CO2
Dalton LAw
total pressure exerted by mixture is sum of pressures exerted by all individuals gases
pressure exerted by individual gas
partial pressure
P gas in dry air
p atm * %gas in atmosphere
p gas in humid air
(p atm- p H2O) * %gas in atmosphere
P(CO2) and P(O2) in atmosphere
PO2=160 mmhg
PCO2= 0.25 mmhg
alveolar partial pressure
PO2= 100mmhg
PCO2= 40mmhg
because of still air
ventilation can vary to match —- with —-
perfusion with ventilation
O2 and CO2 should pass from what barriers in body
epithelial cells and capillary endothelial cells
diffusion if gas is governed by – law
fick
rate of diffusion directlly proportional to
1- surface area (A)
2- membrane permeability (D)
3- partial pressure gradient
rate of diffusion inversely proportional to
1- diffusion distance (T)
membrane thickness
interstitial fluid
diffusion rate
ADdP/T^2
atmosphere and alveoli pressure gradient
O2 will diffuse inside alveoli (160>100)
CO2 will diffuse outside of alveoli to atmosphere(40>0.25)
pulmonary circulation is btw
alveoli and capillary