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Explore the concentration and partial pressure of O2 molecules in air, their transport in solution, and effects of hemoglobin structure. Learn about gas exchange, O2 dissociation curve, CO2 carriage, and more.
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Blood gas transport Lectures on respiratory physiology
CONCENTRATION AND PARTIAL PRESSURE O2 MOLECULES IN AIR DRY AIR: 21% IS OXYGEN [O2] = 21 ml/dl FO2 = 0.21 AsPB = 760 mm Hg PO2 = 0.21 x 760 mm Hg = 160 mm Hg
EFFECT OF WATER VAPOR 37oC PB = 760 mm Hg PH2O = 47 mm Hg PDRY = 713 mm Hg PO2 = 0.21 x 713 mm Hg = 150 mm Hg
O2 IN PHYSICAL SOLUTION 37oC WATER AFTER EQUILIBRATION, AIR: PO2 = 150 mm Hg AIR WATER: PO2 = 150 mm Hg AIR: [O2] = 21 ml/dl WATER: [O2] = 0.45 ml/dl 37oC SOLUBILITY = 0.45 / 150 = 0.003 ml/(dl.mmHg)
TRANSPORT OF O2 IN SOLUTION DURING EXERCISE Solubility = 0.003 ml/(dl.mmHg) PO2 in arterial blood = 100 mm Hg [O2] = 0.3 ml/dl = 3 ml/liter Cardiac output = 30 liters/min Maximum O2 available = 90 ml/min But O2 requirement is 3000 ml/min
Normal cells Sickle cells
ARTERIAL BLOOD VENOUS BLOOD P50 27
TOTAL O2 IN BLOOD IS THE SUM OF Hb-BOUND AND DISSOLVED O2 TOTAL [O2] = 1.39 x [Hb] x % SATURATION/100 + 0.003 x PO2
TOTAL O2 IN ARTERIAL BLOOD (1.39 x 15 x 0.97) + (0.003 x 100) = 20.5 ml/dl
CO-Hb DISSOCIATION CURVE CO SATURATION, % O2 PARTIAL PRESSURE, mm Hg
Carbon dioxide is carried in the • blood in three forms • Dissolved • As bicarbonate • 3. As carbamino compounds
Solubility of Oxygen 0.003 ml/(dl.mmHg) Solubility of Carbon Dioxide 0.067 ml/(dl.mmHg)
Formation of bicarbonate C.A. CO2 + H2O H2CO3 H2CO3 H+ + HCO3-
Formation of carbamino compounds Hb.NH2 + CO2 Hb.NH.COOH