The Power Course

Venous blood vs arterial blood what is untrue


1 ) Venous blood RBC size is more than arterial blood
2 ) Venous blood hematocrit is more than arterial blood
3 ) The RBC chloride content of arterial blood is more than venous blood
4 ) Venous blood carries more CO2 than arterial blood


The solubility of CO2 in the blood is 20 times more than O2.

CO2 diffuses into RBCs readily. Inside, RBC, CO2 is rapidly hydrated by H2CO3 because of the presence of carbonic anhydrase. This forms H+ and HCO3-. H+ is buffered by hemoglobin. HCO3- enters plasma in exchange for Cl-.  This is called a chloride shift. Both bicarbonate and chloride ions are osmotically active so, RBCs swell up and increase in size.  This increased size of RBC and movent fluid into lymphatics increases the venous blood hematocrit by 3%.

Haldane effect

The Haldane effect refers to the increased capacity of deoxygenated hemoglobin to bind and carry CO2. 

This is because deoxygenated hemoglobin binds more readily with CO2. 

Venous blood caban dioxide is more than arterial blood.

The Fate of carbon dioxide in the blood

In Plasma In Red blood cells
Dissolved Dissolved 
Formation of carbamino compounds with plasma protein Formation of carbamino-Hb
 Hydration, H+ buffered, HCO3 in plasma Hydration, H+ buffered, 70% of HCO3 enters the plasma


Approximately 49 mL of CO2 is in each deciliter of arterial blood. In that 2.6 mL is dissolved, 2.6 mL is in carbamino compounds, and 43.8 mL is in HCO3.

In the tissues, 3.7 mL of CO2 is added to each deciliter of blood and the same amount is removed from the lungs from each deciliter of blood.


The RBC chloride content of arterial blood is more than venous blood

Last Modified : 25-Dec-2019

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