The heart is a double pump system in which one pump carries blood poor in oxygen to the lungs and the other pumps oxygen-rich blood through the body. Carbon dioxide in the blood is exchanged for oxygen in the lungs. On any given day, the human heart can pump the body’s entire supply of blood throughout the body around 1,000 times. While the right ventricle supplies the lungs with blood, the left ventricle is designed to pump blood to all other parts of the body. The muscular walls of left ventricles are thicker than the right ventricle muscular walls, which makes the left the more powerful pump.
Blood vessels make up the other major organs in the circulatory system. They reach to all parts of the body and consist of arteries, veins, and capillaries. Arteries are the blood vessels designed to transport blood from the heart to all parts of the body while veins carry blood back to the heart and lungs. Blood travels in a cycle through the lungs, arteries, capillaries, and veins before it comes back through the heart. Nutrient and gas exchange occurs through the capillaries.