The main organ in the circulatory system is the heart, according to Hillendale Health. The two other major parts of the circulatory system are the blood and the blood vessels.
The heart is found slightly to the left at the center of the chest, and it is primarily responsible for pumping blood and keeping the blood moving throughout the body, explains Hillendale Health. Blood is a substance that constantly flows throughout the body, and it is pumped by the heart. It travels through blood vessels and brings water, oxygen, nutrients and waste products to and from the body cells. It consists of liquids, solids and small amounts of oxygen and carbon dioxide.
Clinton Community College explains that the heart is composed of two separate pumps. The right side pumps blood to the lungs, while the left side pumps blood to the body. Both sides have an atrium and a ventricle. The function of the atria is to receive blood while they are relaxed and fill the ventricles as they contract, whereas the ventricles pump blood to the body and lungs.
The main job of the circulatory system is to transport materials throughout the body, says Hillendale Health. The system travels through the entire body and connects all body cells.