1. Lectures on respiratory physiology Acid-Base Balance

2. Some definitions An acid is a molecule that releases hydrogen ions in solution A base is a molecule that can accept a hydrogen ion A buffer is a substance that can reversibly bind hydrogen ions

4. Titration curve for the bicarbonate buffer system

5. CO 2 + H 2 OH + + HCO 3 - [H 2 CO 3 ] [H + ] x [HCO 3 - ] AT EQUILIBRIUM, K = [H + ] x [HCO 3 - ] SOLUBILITY x PCO 2 = H 2 CO 3 CA Law of Mass Action

6. 0.03 x PCO 2 [H + ] x [HCO 3 - ] K = WHICH, AFTER TAKING LOGS, BECOMES : pH = pK + Log ( ) [HCO 3 - ] 0.03 x PCO 2 - THE HENDERSON - HASSELBALCH EQUATION

7. Derivation of normal pH

8. Davenport Diagram

9. PLASMA [HCO 3 - ], meq/l pH pH = 6.1 + Log( ) [HCO 3 - ] 1.2 PCO 2 = 40 7.40 24 NORMAL

10. PLASMA [HCO 3 - ], meq/l pH PCO 2 : 40 30 20 10 60 80 100

11. PLASMA [HCO 3 - ], meq/l pH pH = pK + Log( ) [HCO 3 - ] 0.03 x PCO 2 40 80 20 BUFFER LINE N

12. ACID - BASE DISTURBANCES: * RESPIRATORY ALKALOSIS * RESPIRATORY ACIDOSIS * METABOLIC ACIDOSIS * METABOLIC ALKALOSIS

13. PLASMA [HCO 3 - ], meq/l pH RESPIRATORY ACIDOSIS: 40 80 20 BUFFER LINE H + + HCO 3 - CO 2 + H 2 O N

14. PLASMA [HCO 3 - ], meq/l pH RESPIRATORY ACIDOSIS: 40 80 20 BUFFER LINE H + + HCO 3 - CO 2 + H 2 O N

15. PLASMA [HCO 3 - ], meq/l pH RESPIRATORY ACIDOSIS: 40 80 20 BUFFER LINE H + + HCO 3 - CO 2 + H 2 O N

16. PLASMA [HCO 3 - ], meq/l pH RESPIRATORY ALKALOSIS: 40 80 20 BUFFER LINE H + + HCO 3 - CO 2 + H 2 O N

17. PLASMA [HCO 3 - ], meq/l pH RESPIRATORY ALKALOSIS: 40 80 20 BUFFER LINE H + + HCO 3 - CO 2 + H 2 O N

18. PLASMA [HCO 3 - ], meq/l pH METABOLIC ACIDOSIS: 40 80 20 BUFFER LINE H + + HCO 3 - CO 2 + H 2 O N

19. PLASMA [HCO 3 - ], meq/l pH METABOLIC ACIDOSIS: 40 80 20 BUFFER LINE H + + HCO 3 - CO 2 + H 2 O N

20. PLASMA [HCO 3 - ], meq/l pH METABOLIC ALKALOSIS 40 80 20 BUFFER LINE H + + HCO 3 - CO 2 + H 2 O

21. PLASMA [HCO 3 - ], meq/l pH METABOLIC ALKALOSIS 40 80 20 BUFFER LINE H + + HCO 3 - CO 2 + H 2 O

22. PLASMA [HCO 3 - ], meq/l pH COMPENSATED RESPIRATORY ACIDOSIS 40 80 20 BUFFER LINE COMPENSATED METABOLIC ALKALOSIS

23. Oxygen Delivery to Tissues

24. CAPILLARIES DIFFUSION HEART AND CIRCULATION TISSUE VENTILATION THE OXYGEN TRANSPORT SYSTEM LUNGS PERFUSION DIFFUSION

25. Fick equation for diffusion through a tissue sheet

26. Distribution of PO 2 between capillaries

27. Critical PO 2 for mitochondrial respiration

28. Classification of tissue hypoxia: * Anemic hypoxia * Hypoxic hypoxia * Circulatory hypoxia * Histotoxic hypoxia