Question

How much oxygen is supplied by blood to tissues in one circulation in normal condition:-

• A. 75%
• B. 4%
• C. 25%
• D. 20%

Answer 1

Answer: (B)

4%

Haemoglobin is the major iron-containing pigment that helps in the transport of gases. Each haemoglobin molecule can carry a maximum of four molecules of oxygen. Binding of oxygen with haemoglobin is primarily related to partial pressure of O${}_2$. In 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. In tissues,where low pO${}_2$, high pCO${}_2$, high H${}^{+}$ concentration and high temperature exist, the conditions favourable for dissociation of oxygen from the oxyhaemoglobin. Every 100 ml of oxygenated blood can deliver around 4 ml of O${}_2$ to tissues under normal physiological conditions. A 100ml of oxygenated blood can carry 20ml of O${}_2$. However, only 4 ml is delivered to the tissues.

Thus, the correct answer is '4%.'