Question

What do you understand by double circulation? Explain transport and exchange of oxygen and carbon dioxide with the help of schematic representation (diagram).

Answer 1

Double circulation is a process during which the blood passes two times the heart in one cycle. The heart is four chambered.

The movement of blood in an organism is divided into two parts:

(i) Systemic circulation

(ii) Pulmonary circulation

Systemic circulation involves the movement of oxygenated blood from the left ventricle of the heart to the aorta. It is then carried by blood through a network of arteries, arterioles, and capillaries to the tissues. From the tissues, the deoxygenated blood is collected by the venules, veins, and vena cava, and is emptied into the left auricle.

Pulmonary circulation involves the movement of deoxygenated blood from the right ventricle to the pulmonary artery, which then carries blood to the lungs for oxygenation. From the lungs, the oxygenated blood is carried by the pulmonary veins into the left atrium.

Hence in double circulation, blood has to pass alternately through the lungs and the tissues.