WORKING OF THE CIRCULATORY SYSTEM
The human heart acts as a double pump, Blood comes to the heart twice on one complete circulation around the body. This is called a double circulation.
In the right atrium, blood from the whole body comes back through two large veins called vena cava. It has less amount of oxygen. When right atrium contracts blood is pushed into right ventricle. From this chamber, the blood is pumped outthrough pulmonary artery to the lungs. In the lungs, blood collects oxygen from the inhaled air and gives up its carbon dioxide. This oxygenated blood from the lungs returns to the left atrium throughpulmonary veins. When left atrium contracts, it is pushed into left ventricle.
From this chamber of the heart, the blood through a large artery called Aorta is carried to the upper parts and to the lower parts of the body
