The circulatory system is made up of only a couple of organs. These include the heart and blood vessels. The heart functions to pump blood and distribute oxygen to the different parts of the body through blood vessels. This organ also transports oxygen-depleted blood through blood vessels back to the lungs to pick up oxygen.
The heart is a grapefruit-sized organ located between the lungs. The organs in the circulatory system are made out of a very special type of muscle called cardiac muscle, which works constantly without rest and does not tire. This special type of muscle is found nowhere else in the body. It exists solely in the heart.
Four hollow chambers make up the interior of the heart. The atria consists of the heart's two upper chambers while the two lower chambers make up the ventricles. Chambers are separated by one-way valves, which are designed to keep blood from flowing in the wrong direction through the circulatory system. As blood flows through the chambers of the heart, valves open and close, which creates the traditional “heart beat” noise.
Blood is an essential component for the organs in the circulatory system. This material carries substances through the body, including oxygen and carbon dioxide. The oxygen in blood reacts with the sugar in cells to create energy. Carbon dioxide and the other waste created from this process are carried away through the blood.
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.