Transport of carbon dioxide in the blood Flashcards
Does arterial blood contain more oxygen or more carbon dioxide?
More carbon dioxide
What are the different forms of carbon dioxide in the blood?
Dissolved
Reacted
Bound to haemaglobin
What are the different forms of carbon dioxide in the blood from most common to least common?
Reacted
Bound to haemoglobin
Dissolved
What does dissolved carbon dioxide in the plasma do?
Some of it reacts
Some of it diffuses across red blood cell membranes into red blood cells
How does carbon dioxide react in the plasma?
Carbon dioxide + water carbonic acid
What does carbonic acid do in the plasma?
Carbonic acid bicarbonate + hydrogen ion
this occurs very quickly
What does dissolved carbon dioxide in red blood cells do?
Some of it reacts
Some of it binds to haemaglobin
How does dissolved carbon dioxide in red blood cells react?
Carbon dioxide + water bicarbonate + hydrogen ion
What enzyme catalyses the reaction
carbon dioxide + water bicarbonate + hydrogen ion?
Carbonic anhydrase
What effect does carbonic anhydrase have on the reversible reaction
carbon dioxide + water bicarbonate + hydrogen ion?
Increases the rate of both the forward and backward reactions equally
What happens to bicarbonate ions in red blood cells?
AE transports bicarbonate ions from the red blood cells into the plasma
and chloride ions from the plasma into the red blood cell
How does carbon dioxide bind to haemaglobin?
Binds to amine groups of globin chains
What is the reacted form of carbon dioxide?
Bicarbonate ions
What is the name of carbon dioxide bound to haemaglobin?
Carbaminohaemaglobin
What happens to pCO2 at tissue capillaries? Why?
Increases
because tissue metabolism produces CO2
What happens to the amount of carbaminohaemaglobin at tissue capillaries? Why?
Increases
high pCO2 causes oxygen to be released from haemaglobin by Bohr effect
carbon dioxide binds to it
What happens to the amount of bicarbonate ions at tissue capillaries? Why?
Increases
because haemaglobin in its tense state more hydrogen ions bind to it favours forward reaction more bicarbonate ions produced more transported into plasma
What happens to pCO2 at pulmonary capillaries? Why?
Increases
because of the Haldane effect
What is the Haldane effect?
Binding of oxygen to haemaglobin
causes carbon dioxide to be released from haemaglobin
also puts haemaglobin in its relaxed state fewer hydrogen ions bind to it favours backwards reaction more carbon dioxide produced diffuses into plasma
What happens to carbaminohaemaglobin at the pulmonary capillaries?
Dissociates into haemaglobin and carbon dioxide
What happens to the increased carbon dioxide at the pulmonary capillaries?
Diffuses into the alveoli
expired from the alveoli
