Describe6 marksChallenge
A medical researcher is investigating how carbon dioxide (CO₂) produced by respiring tissues is transported in the blood to the lungs for exhalation. She measures the CO₂ content in arterial and venous blood samples and finds that approximately 85% of the CO₂ is carried as bicarbonate ions (HCO₃⁻), 10% is bound to haemoglobin as carbaminohaemoglobin, and 5% is dissolved directly in plasma.
Describe the mechanisms by which CO₂ is loaded into the blood at the tissues and unloaded at the lungs. In your answer, include the roles of:
- red blood cells
- haemoglobin
- carbonic anhydrase
- the chloride shift
- plasma
- the Bohr shift