1. TRANSPORT OF RESPIRATORY GASES BY BLOOD

2. OXYGEN TRANSPORT  Bound to hemoglobin  Dissolved in plasma  1.5% of the oxygen transported is carried in the dissolved form.  98.5% of the oxygen is carried from lungsto tissues in a loose chemical combination with hemoglobin.

3. Association of Oxygen and Hemoglobin  Hemoglobin is composed of four polypeptide chains.  Each bound to an iron-containing heme group  Four molecules of O2  Oxyhemoglobin HbO2  Reduced hemoglobin, or deoxyhemoglobin

4. The rate at which Hb reversibly binds or releases O2 is regulated by :  PO2  temperature  blood pH  PCO2  organic chemical called BPG.

5. Influence of PO2 on Hemoglobin Saturation  PO2 measurements indicate only the amount of O2 dissolved in plasma.  PO2 values are a good index of lung function.