1. Ventilation/Perfusion Ratios in the Lung

2. O 2 Transport in the Blood O 2 is bound to hemoglobin (Hb) for transport in the blood –Oxyhemoglobin: O 2 bound to Hb –Deoxyhemoglobin: O 2 not bound to Hb

3. Oxyhemoglobin Dissociation Curve

4. O 2 -Hb Dissociation Curve: Effect of pH Blood pH declines during heavy exercise Results in a “rightward” shift of the curve –Bohr effect –Favors “offloading” of O 2 to the tissues

5. pH and O2-Hem Diss. Curve

6. O 2 -Hb Dissociation Curve: Effect of Temperature Increased blood temperature results in a weaker Hb-O 2 bond Rightward shift of curve –Easier “offloading” of O 2 at tissues

7. Temp. and O2-Hem Diss. Curve

8. O 2 Transport in Muscle Myoglobin (Mb) shuttles O 2 from the cell membrane to the mitochondria Higher affinity for O 2 than hemoglobin –Even at low PO 2 –Allows Mb to store O 2

9. Diss. Curve - Myoglobin vs. Hemoglobin

10. CO 2 Transport in Blood Dissolved in plasma (10%) Bound to Hb (20%) Bicarbonate (70%) –CO 2 + H 2 O  H 2 CO 3  H + + HCO 3 - –Also important for buffering H +

11. 3 Forms of CO2 Transport in Blood

12. CO2 Exchange in Lung

13. Ventilation and Acid-Base Balance Blood pH is regulated in part by ventilation An increase in ventilation causes exhalation of additional CO 2 –Reduces blood PCO 2 –Lowers H + concentration

14. Transition from Rest to Steady State

15. Exercise in a Hot Environment During prolonged submaximal exercise: –Ventilation tends to drift upward –Little change in PCO 2 –Higher ventilation not due to increased PCO 2

16. Ventilation vs. Hot/Humid

17. Respiratory Parameters (Elite vs. Untrained)