Submitted by LemmeKermitSuicide t3_z8ssc4 in askscience
LemmeKermitSuicide OP t1_iydg4nx wrote
Reply to comment by dan_dares in How is O2 introduced to blood in the alveoli? by LemmeKermitSuicide
Ah, I see. Does the O2 molecule need a certain energy to pass over the wall? Is it possible to pass over the wall and not bind to a hemoglobin?
Edit: membrane to wall
FireteamAccount t1_iydhvh6 wrote
Passive diffusion requires no added energy. The difference in oxygen concentration on either side of the wall is all the chemical potential energy required.
threegeeks t1_iydmsoj wrote
Does that mean it's iron-ic...
Sorry, that just popped into my head.
Neat chapter on oxygen transport over on NLM: https://www.ncbi.nlm.nih.gov/books/NBK54103/
MECHASCHMECK t1_iye931i wrote
Not really! Like others have said, it’s passive diffusion based on the pressure gradient between the air and venous blood. The partial pressure of O2 in the air we breath is about 159 mmHg, about 100 mmHg in your alveoli (average since it’s constantly diffusing), and about 35 mmHg in your venous blood. Transfer occurs in the direction of high to low, so O2 heads for the blood, and CO2 heads out to the air 50 venous to 0.3 air).
sterfri99 t1_iydn835 wrote
To answer your other question, a small amount of oxygen is dissolved in the plasma (~0.3ml O2/100ml blood) and doesn’t bind to hemoglobin.
This here is a great place to learn more https://www.cvphysiology.com/Microcirculation/M002
[deleted] t1_iydu4yb wrote
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[deleted] t1_iyepwz4 wrote
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