<prompt> Normal PCO2 of arterial blood is:20 mmHg40 mmHg60 mmHg80 mmHg  <response>: Ans: b 40 mmHg. Ref:Ganong, 22nd ed, p. 607Partial pressure mmHg Arterial bloodVenous bloodPO29540PCO24046Carrying capacityoxygen19.6mldl15.6mldl Carbon dioxide49mldl53mldl1 gm Hb can carry 1.39 ml of oxygen, when fully saturated.1.34 ml oxygen in vivo.1 gm Hb carries 3.34 mg Iron in it.Oxygen entering the body per minute 250 ml.Oxygen leaving the body per minute 200 ml 288Lday.PH of arterial blood - 7.4 and pH of venous blood - 7.36Haematocrit of venous blood increase by 3Chloride shift takes about 1 second to occur. 