Physiology-CO2 Transport Flashcards
(16 cards)
The pressure differential for CO2 is very minimal. How then does CO2 get expelled from the body?
The solubility of CO2 in fluid is very high and the molecular weight is small. This makes for a high diffusion coefficient to accommodates for the low pressure differential.
How are you able to get rid of CO2 in the lungs when you are working out and blood is flowing faster?
Diffusion is fast and efficient and all the CO2 gets out of the capillary in the first 1/3.
How is CO2 transported through the blood?
Dissolved CO2, bicarbinate anions or carbamino compounds.
How much of the CO2 produced by cells is transported as dissolved CO2 in the blood?
7.00%
How is most CO2 transported in the blood? Where does this method of transport pass through?
Bicarbonate (70%). Carbonic anhydrase catalyzes the reaction in RBCs and is 5000x faster than in plasma.
Where do you expect to find RBCs with higher Cl- concentration? Why?
In venous blood, this is where most CO2 is in the vasculature. Facilitated diffusion via the bicarbonate-chloride exchanger protein is what allows bicarbonate produced from CO2 to get into the blood stream and out of the body.
The majority of carbonic acid production occurs in the red blood cells because they have the enzyme carbonic anhydrase. How does the RBC handle increased H+ from this reaction?
Deoxyhemoglobin has a high affinity for H+. Thus, it acts as a buffer for the H+ produced by carbonic anhydrase.
How is CO2 transported as a carbamino compound?
High concentration of hemoglobin in RBCs allows for binding of CO2 to Hgb and then transport through the blood.
What roles does hemoglobin play in CO2 transport?
Direct transport as a carbamino compound and H+ buffer inside the RBC.
What is the Haldane effect?
CO2 bound to hemoglobin is released more effectively as oxygen binds to hemoglobin. This aids in increased CO2 release (2x greater) at the pulmonary capillaries.
What happens to the CO2 “transporters” at the alveoli?
Hb binds O2 and releases CO2 and H+. CO2 diffuses. H+ forms carbonic acid, which then forms CO2 and that CO2 diffuses.
How does venous blood pH compare with arterial blood pH?
Venous = 7.37. Arterial = 7.41. This is due to increased CO2 in the venous system, increased bicarbonate production and H increased H+ in the venous system.
How can you figure out blood pH if you only know the blood bicarbonate concentration and PCO2?
Henderson-Hasselback equation.
What does this diagram even tell you?
This is a Davenport diagram. It shows the relationship between kidney (HCO3 control on curves) and the lungs (PCO2 on the line) on blood pH.
A patient comes to see you with decreased alveolar ventilation due to drug overdose. His arterial PCO2 is 50mmHg and blood pH is 7.3. How will his body fix respiratory acidosis?
The kidney will begin making more HCO3 to bind up H+ and return blood pH back to 7.4.
A patient comes to see you with increased alveolar ventilation due to anxiety. Her arterial PCO2 is 30mmHg and blood pH is 7.5. How will her body fix respiratory alkalosis?
The kidney will make less HCO3 to release more H+ and return blood pH back to 7.4.
