How does the cardio-vascular system work?

Answer 1

The right atrium and right ventricle pump deoxygenated blood from the body to the lungs via the pulmonary artery. Carbon dioxide is then exchanged for oxygen in the capillaries of the lungs. The oxygenated blood then travels from the lungs, via the pulmonary vein to the left atrium and left ventricle, and then is pumped to the rest of the body to feed the cells.

Answer 2:

The heart is a four-chambered muscular organ that pumps blood to all parts of the body. A wall, called a septum, divides the heart into a right and left side. Each side is further divided in to an upper chamber (called the atrium) and a lower chamber (called the ventricle). These chambers are separated by valves that open and close to direct blood flow through the heart. Blood is pumped through the body delivering oxygen and nutrients to all parts of the body. The blood then returns to the right side of the heart. From there, the blood is pumped to the lungs where it is receives a fresh supply of oxygen. The left side of the heart receives this blood from the lungs and pumps it through arteries to your heart muscle and other parts of your body. This happens thousands of times a day.