Question

Dissociation of oxyhaemoglobin occurs in tissues due to

• A. High $p_{O2}$
• B. Low $p_{O2}$
• C. Equal $p_{O2}$
• D. Irrespective of $p_{O2}$

Answer 1

The correct option is B Low $p_{O2}$

In the alveoli, where there is high pO${}_2$, low pCO${}_2$, lesser H+ concentration and lower temperature, the factors are all favourable for the formation of oxyhaemoglobin, whereas in the tissues, where low pO${}_2$, high pCO${}_2$, high H+ concentration and higher temperature exist, the conditions are favourable for dissociation of oxygen from the oxyhaemoglobin. This clearly indicates that oxygen gets bound to haemoglobin in the lung surface and gets dissociated at the tissues. Every 100 ml of oxygenated blood can deliver around 5 ml of O${}_2$ to the tissues under normal physiological conditions.

Therefore, the correct answer is option B.