Respiratory 28 Flashcards
What are the three forms that carbon dioxide is carried in?
- Dissolved (5%)
- Bicarbonate (HCO3- 60 - 65%)
- Carbamino compounds (25 - 30%)
What causes CO2 to diffuse out of the cells into interstitial fluid?
An increase in PCO2 in the cells and a low PCO2 in interstitial fluid which causes a pressure gradient
What happens after carbon dioxide moves into red blood cells?
It can react with water to produce carbonic acid in the presence of carbonic anhydrase. The carbonic acid then dissociates into hydrogen ions and bicarbonate
How is Bicarbonate able to exit the RBC cell?
RBCs exchange bicarbonate for chloride using the anion exchange protein
What does Chloride shift refer to?
The exchange of bicarbonate in RBCs with Chloride anions
What decreases the pH of blood?
The hydrogen ions in RBCs that form as a result of carbonic acid forming bicarbonate and H+ ions
How is carbon dioxide carried by Carbamino Compounds?
CO2 combines with amino groups in blood proteins (globins in Hb) to form HBCO2
What does Carbon dioxide have a higher affinity for; Oxyhemoglobin or Deoxyhemoglobin?
Carbon dioxide has a higher affinity for deoxyhemoglobin
What does Carbon Dioxide having a higher affinity for deoxy hemoglobin do?
CO2 helps to unload O2 from Hb in peripheral tissue
How does an increase in PCO2 affect the oxygen dissociation curve?
It will cause the curve to shift to the right and there will be a lower percentage of hemoglobin that is bound to oxygen. Meaning that in the presence of high levels of CO2 there will be increased oxygen unloading from the hemoglobin because carbon dioxide will preferentially bind to deoxyhemoglobin
What happens to carbon dioxide at the level of the alveoil?
A pressure gradient will cause it to flow into the alveoli. Bicarbonate flows into the RBCs and react with hydrogen ions to produce carbonic acid and then carbon dioxide. Deoxyhemoglobin will be shifted so it does less binds to carbon dioxide
What happens to the hydrogen ions produced when carbonic acid forms bicarbonate and H+?
Hydrogen ions have a higher affinity for deoxyhemoglobin and hydrogen ion binding to hemoglobin favors the unloading of oxygen from hemoglobin in peripheral tissues
What are the important effects of the interaction of hemoglobin binding to hydrogen ions?
- Increased unloading of oxygen in peripheral tissues
* Increased H+ does not change the plasma of the blood due to buffering of hemoglobin
What occurs in respiratory acidosis?
Hypoventilation causes CO2 production to be greater than elimination so PCO2 increase and H+ increases
What occurs in respiratory alkalosis?
Hyperventilation causes CO2 production to be less than CO2 elimination so PCO2 decreases and H+ decreases
