double circulation

It prevents mixing of oxygenated and deoxygenated blood and keeps them separate.

This type of circulation provides highly efficient supply of oxygen to the body. This is useful in endothermic animals like mammals and birds, having high energy needs.

 

 

Another advantage over the single circulatory system is that for each circulation the blood has to pass through only one set of capillary networks before returning to the heart. This helps to maintain a higher blood pressure and a higher speed of flow of the blood. In turn this helps to maintain steeper diffusion gradients than in animals with single circulation and so the exchange of metabolites (oxygen etc.) is more efficient.