1. majority carried in blood as hydrogencarbonate ions (synoptic to AS) - this creates hydrogen ions. This occurs in the RBC under the influence of carbonic anhydrase (enzyme). Hydrogen ions combine with haemoglobin, so have to compete with oxygen - too much cardon dioxide reduces oxygen transport
2. carbon dioxide combines directly with haemoglobin to form carbaminohaemoglobin - this molecule has lower affinity for oxygen than normal haemoglobin
3. excess carbon dioxide can casue respiratory acidosis. Carbon dioxide dissolves in the blood plasma and once dissolved it can combine with water to produce carbonic acid which dissociates to release hydrogen ions
Hydrogen ions low pH - blood more acidic. Proteins in blood act as buffer to resist the change in pH. If change is small, pH detected my medulla oblongata which causes increased breathing rate to remove carbon dioxide quicker. Big change (drops below 7.35) = difficult breathing, rapid heart rate and changes in blood pressure ---> respiratory acidosis
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