<prompt> Partial pressure of oxygen in alveoli:60 mmHg103 mmHg136 mmHg160 mmHg  <response>: Ans. b 103 mmHgRef: Harrison 18th edition, Chapter 252Partial Pressures of blood gases Atmosphere: pO2160mmHg, pCO20.3mmHg Alveolar air: pO2l05mmHg, pCO240mmHg Oxygenated blood: pO2100mmHg, pCO240mmHg Tissues: pO240mmHg, pCO245mmHg Deoxygenated blood: pO240mmHg, pCO245mmHgMust KnowO2 and CO2 in blood 1.5 O2 dissolved in blood 98.5 O2 carried by hemoglobin Hb-O2 Hb can carry up to four molecules of O, four saturation PO2 determines Hb saturation Also pH, temperature and Pco2 affects Hb-O2 binding 