Oxyhaemoglobin dissociation curve

Figure 6.13 The effect of different concentrations of 2,3-bisphosphoglycerate on the oxyhaemoglobin dissociation curve. The increase in the concentration of BPG from 4 to 5 mmol/L results in an increase in the amount of oxygen released in the capillaries by more than 20%. The concentration of BPG decreases on storage of erythrocytes, so that cells from the blood bank have a higher affinity for oxygen and hence discharge less oxygen in the tissue.

Fig. 27. Dissociation curves for /) oxyhaemoglobin in solution 2) oxyhaemoglobin in human red cells and 3) immobilized haemoglobin. 37 °C, pH 7.4 pC02 40 Torr, p02 0-150 Torr...

The oxyhaemoglobin (oxy-Hb) dissociation curve is core knowledge for the examination and in clinical practice. You will be expected to have a very clear understanding and to be able to construct a very precise graph. 

The concentration in the erythrocytes of 2,3-bisphosphoglycerate that influences the dissociation curve of oxyhaemoglobin (Chapter 6). 

However it is necessary to compare values of pto obtained under comparable conditions. Changes in temperature and pH displace the dissociation curve. The combination of molecular oxygen with a carrier being an exothermic process, an increase in temperature will lower the affinity, and a decrease in temperature will increase it. Figure 87 illustrates the shift in the dissociation curve of the oxyhaemoglobin of the ray Rata ocellata with temperature. 

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