Human blood must have a pH between 7.35 and 7.45 - any deviation from this value causes serious illness and death. Blood contains a buffer consisting of carbonic acid (H2CO3) and bicarbonate anions (HCO3). It forms an equilibrium shown below: H30* + HCO3 = H2CO3 + H20 The carbonic acid forms as a result of CO2 being in equilibrium with water. H2CO3 = H2O + CO2 When we breathe, we inhale oxygen and exhale carbon dioxide. The bicarbonate anion is produced by the kidneys. The Figure under the answer box below shows the buffer curve for the pH of blood. You are an emergency medicine doctor. You have a patient with respiratory alkalosis, which occurs when the lungs exhale too much CO2. i. What would happen to the pH of your patient's blood? ii. If someone's pH increases above 7.8, they die. How much would the % buffer have to shift from normal blood pH to endanger your patient's life? iii. What could you suggest to help your patient? % buffer in the form of HCO, 25 50 75 100 8 Normal blood pH 7 Region of maximum buffering capacity pH 6 6 pk =6.1 5 5 100 50 75 25 % buffer in the form of H,Co, and CO2 Figure for the question 9-3.4