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Respiratory Phys 6
WVSOM -- Gas Transport in the Blood
| Question | Answer |
|---|---|
| What are the general hemodymamic characteristics of the pulmonary circulation? | low pressure, high flow, low resistance |
| How does an increase in pulmonary arterial pressure reduce pulmonary resistance? | recruitment and distention of capillaries |
| How is oxygen carried in the blood? | hemoglobin and dissolved |
| How much oxygen is carried in hemoglobin? | 10.8ml O2/100ml of blood |
| How much oxygen is dissolved in the blood? | 0.3ml O2/100 ml of blood |
| When does Hb give up O2? | at low tissue PO2 |
| What is the steep region of the oxygen dissociation curve? | Hb gives up O2 at low tissue pressures |
| How is total O2 content calculated? | dissolved O2 + Hb bound O2 |
| When is Hb saturation % misleading? | CO poisoning and anemia |
| Why is Hb saturation % misleading in anemia? | the Hb available is saturated but there is less Hb available for being bound. |
| Why is Hb saturation misleading in CO poisoning? | CO is bound to hemoglobin showing a high saturation but there is not O2 available to be bound to Hb |
| What happens when there is a left shift of the HbO2 dissociation curve? | Hb holds on more readily to O2 |
| What causes a left shift in the HbO2 dissociation curve? | Decrease in temperature, DPG, Pco2, and H+ |
| What causes a right shift in the HbO2 dissociation curve? | increase in Temp, DPG, Pco2 and H+ |
| What happens when there is a right shift in the HbO2 dissociation curve? | Hb gives up O2 more readily |
| Where is the O2 dissociation curve right shifted? | venous bood |
| What is the PO2/SaO2 in the veins? | 40/75% |
| What changes will cause a right shift of the O2 dissociation curve? Decreased temperature, decreased Pco2 or Decreased pH? | decreased pH |
| What three forms is CO2 transported in? | HCO3, dissolved and carbamino |
| How much CO2 is carried in bicarb? | 60% |
| What are carbamino? | protiens that carry CO2, carrie 30% of CO2 |
| How much CO2 is dissolved? | 10% |
| What is the main facilitator of CO2 transport? | RBC |
| Why is RBC the main facilitator of CO2 transport? | all reactions of CO2 transport occur in the RBC |
| How is the CO2 dissociation curve compared to the O2 dissociation curve? | more linear and steeper |
| What kind of partial pressure changes are needed to unload a large amount of CO2? | small partial pressures |
| What decreases the blood from its ability to carry CO2? | oxygenation |
| What is the Haldane effect? | oxygenation of the blood decreases the ability to carry CO2; deoxygenation in the tissues helps with loading CO2 |
| What two things explain the the actions of reduced hemoglobin in the Haldane effect? | dexoygenated hemoglobin is monopolized by H+ pulling equilibrium to the right and oxygenated Hb forms more Carbamino compounds |
| What does the HCO3:CO2 ratio determine? | pH |
| What is the normal HCO3:CO2 ratio resulting in a pH of 7.4? | 20 |
| What is a respiratory disturbance? | when there is a Pco2 disturbance |
| What is a metabolic disturbance? | when there is a bicarbonate disturbance |
| What causes respiratory acidosis? | Increased Pco2 |
| What causes respiratory alkalosis? | Decreased Pco2 |
| What will restore the ratio when there is respiratory acidosis? | increased bicarb |
| What will restore the ratio when there is respiratory alkalosis? | decreased bicarb |
| What causes metabolic alkalosis? | increased bicarb |
| What causes metabolic acidosis? | decreased bicarb |
| What will restore the ratio with metabolic alkalosis? | hypoventilation |
| What will restore the ratio with metabolic acidosis? | Hyperventilation |
| What is the primary disturbance in respiratory acidosis? | increased Pco2 |