Transport Of CO₂ Flashcards
In what 3 ways is CO₂ transported?
5% dissolved in plasma
10% combined with haemoglobin to form carbaminohaemoglobin
85% in form hydrogencarbonate ions (HCO₃⁻)
How do hydrogencarbonate ions form?
1) CO₂ diffuses into RBC
2) combines with water –> carbonic acid (carbonic anhydrase enzyme)
3) carbonic acid dissociates to release H⁺ and hydrogencarbonate ions
What happens after hydrogencarbonate ions are formed?
they diffuse out of the RBC to the plasma which affects the charge in the RBC
What is the chloride shift?
the movement of chloride ions into the erythrocytes (from plasma) to balance the charge as hydrogencarbonate ions leave the cell
What about the hydrogen ions?
Building up in RBC could cause it to become very acidic. To prevent this, they are taken out of solution by associating with haemoglobin (after it dissociates with O₂) —> haemoglobinic acid (haemoglobin acting as buffer, maintains pH)
What is the Bohr effect?
the effect that extra CO₂ has on haemoglobin, explaining the release of more O₂
the hydrogen ions affect the pH in RBC making more acidic so affects tertiary structure of haemoglobin and reduces its affinity for oxygen. It’s unable to hold as much O₂ so releases it to tissues
Where tissues are respiring more ____
more CO₂ released, more H⁺, more O₂ released
What is the Bohr shift?
haemoglobin dissociation curve shifts downwards and right because more CO₂ is present
