CBSE Class 10 Answered

The deoxygenated blood from body is taken to the heart through veins. This blood first enters the right auricle from vena cava (both inferior and superior) and then via the tricuspid valves, it goes to right ventricle. Now , from here the deoxgenated blood goes to lungs for purification via pulmonary arteries .After purification , the oxygenated blood is transferred to left auricle via the pulmonary veins . From left auricle , it goes to left ventricle via the bicuspid valve.Now, from here it released out through aorta and is distributed in the body via arteries.In this process the blood enters twice the heart, so this process is called double circulation .