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level: transportation of oxygen and carbon dioxide

Questions and Answers List

Question	Answer
- inspired air: 21% oxygen, 0.04 carbon dioxide - expired air: 16% oxygen. 4% carbon dioxide - other % made up of nitrogen and water vapour	percentage of gas
- maintained by constant flow of blood through the capillaries, always replaces by more blood pumping around the body, the new blood is low in oxygen and high in carbon dioxide - maintained by the continual movement of air in and out of the alveoli as we breath in and out, new air is low in carbon dioxide and high in oxygen	concentration gradient
- oxygen is carried: 3% dissolved in blood plasma, 96% as oxyghaemoglobin - Hb + O2 <-> HbO2: oxygen combines with haemoglobin where oxygen concentration is high - oxygenated blood is blood with a high proportion of oxyhaemoglobin - oxyhaemoglobin breaks down into oxygen and haemoglobin where oxygen concentrations are low - oxygenhaemoglobin is bright red in colour, so the blood in the arteries is bright red - haemoglobin is dark red or purplin in colour, the deoxygenated blood in veins is therefore dark red	oxygen gas
- carbon dioxide is carried: 7-8% dissolved in plasma, 22% coined withe the globin part of haemoglobin (forms carbaminohaemoglobin), 70% carried in plasma in bicarbonate ions - blood in the capillaries: most carbon dioxide reacts with water to form carbonic acid (H2CO3) - carbonic acid then dissolves into hydrogen ions and bicarbonate ions - CO2 + H20 <-> H2CO3 <-> H + HCO3	carbon dioxide gas