Dalton's Law of Partial Pressures
Total pressure produced by a mixture of gasses = sum of pressures
produced by each
Atmosphere pressure (sea level)
760 mm Hg
PO2= Inside alveolus in lungs
104 mm Hg
PCO2= Inside alveolus in lungs
40 mm Hg
PO2 level inside capillaries carrying deoxygenated blood
40 mm Hg
Oxygen moves from alveolus (lungs) to blood and blood PO2
increases to
104 mm Hg
Blood carries oxygen from lungs to tissues and mixes with...
deoxygenated blood and drops PO2 to 95 mmHg
The tissues have a PO2 of
40 mm Hg
Oxygenated blood diffuses into tissues due to the
partial pressure gradient
O 2 travels from higher to
lower partial pressure
When O2 leaves blood and goes into tissues the
PO2 level drops to
40 mm Hg
The tissues produce CO2 .The level of PCO2 in
the tissues is
45 mm Hg
CO2 follows partial pressure gradient and diffuses into
blood increasing PCO2 to
45 mm Hg
CO2 from tissues carried to lungs, the alveolar
PCO2 in lungs is
40 mm Hg
CO2 follows partial pressure gradiant and diffuses out of
blood into alveoli, blood PCO2 drops to
40 mm Hg
Complete pathway of O2 from Alveolus to Tissues:
Alveolous PO2 104 mmHg Blood circulation
PO2 104 drop to 95 mmHg Diffuses(higher to
lower conc.) into tissues that have PO2 of 40 mmHg
Blood PO2 drops down to 40mmHg
Oxygen moves from areas of _________ to _________PO2
higher; lower
Carbon dioxide move from areas of ________to ______PCO2
higher; lower
Complete pathway of CO2 from tissues to alveolus/lungs
Tissues PCO2 45 mmHg Diffuses into blood
PCO2 from 40 to 45 mmHg Diffuses into
lungs/alveoli that have a PCO2 from 40 to 45 mmHg
Exhaled out of body