Diffusion Flashcards
method of O2 and CO2 diffusion
passive diffusion
Normal pO2 on alveolus, pulm art, pulm vein
alv - 100
art - 40
vein - 90
Normal pCO2 on alveolus, pulm art, pulm vein
alv - 40
art - 47
vein - 40
3 important alveolar cells
type 1 and 2 pneumocytes, macrophages
method of air travel from mouth to alveolus
bulk flow
name of “holes” between alveoli
pores of kohn
5 ways to improve diffusion across membrane
- larger membrane surface area
- more pressure
- incr. membrane solubility
- thinner membrane
- smaller molecule (low MW)
Law that sums up movement across membrane
Ficks law
Which will diffuse faster O2 or CO2 and why
CO2, larger molecular weight, but 20 times as soluble
definition of diffuse limited
diffusion across membrane is rate limiting step
what makes something diffusions limited (3)
- not affected by perfusion
- carried by blood in sig. quantities
- cannot diffuse rapidly across alveoli
example of diffusion limited gas and use
CO - measure diff. capacity
what makes something perfusion limited
- very soluble
- rapid membrane transit
- not carried in great quantities in blood
exmaple and use of perfusion limited gas
NO2 to measure cardiac output
at rest, how are O2 and CO2 limited
perfusion limited
during excersise, how are CO2 and O2 limited
O2 - diffusion
CO2 perfusion - always very soluble
how to measure diffusion
single breath of CO He and O2 mix
- measure amount of diffused CO
2 steps to get gas from alv to body
- cross membrane
2. bind to Hgb
3 blood realated probs with diffusion
- low volume
- low Hb
- embolism
why is He in diffusion test
to measure the TLC
how does He dilution test work
give He and use C1V1=C2V2
what does it mean is He measured vol is much lower that pleth volume
blockage
what will happen to DLCO in anemia
down
what will happen to DLCO in polycythemia
up
