how many different ways is carbon dioxide transported by?
3
what are the 3 different ways that carbon dioxide is transported by?
in solution in the plasma (approximately 5%)
as the hydrogen carbonate ion - HCO3−(approximately 85%)
bound to haemoglobin as a carbamino-haemoglobin (approximately 10%)
what is another way that some carbon dioxide is transported?
some carbon dioxide is transported in the red blood cells but most is converted in the red blood cells to hydrogen carbonate, which then diffuses into the plasma
how can you describe the reactions in red blood cells?
CO2 in the blood diffuses into the redblood cell
carbonic anhydrasecatalyses the combination of CO2 with H2O, making carbonic acid
carbonicaciddissociates into H+and HCO3−ions
HCO3−ions diffuse out the redblood cell into plasma
to balance the outflow of -ions and maintain electrochemicalneutrality, chloride ions diffuse into the red blood cell from the plasma - this is called the chloride shift
H+ions cause oxyhaemoglobin to dissociate into oxygen and haemoglobin-H+ions combine with haemoglobin to make haemoglobinic acid, HHb, which removes H+ions and so pH of red blood cell doesn’tfall
oxygendiffuses out of the redbloodcell into the tissues
how does haemoglobin buffer the blood?
by removing hydrogen ions from solution, preventing the pHfalling
what is the chloride shift?
the diffusion of chlorideions from the plasma into the redbloodcell, preserving electricalneutrality
