Blood begins its journey through the body from the heart. The heart is an organ that pumps blood into the rest of the body.

After leaving the heart, the blood travels through the aorta. The aorta is divided into smaller blood vessels known as arteries. Arteries transport blood from the heart into all parts of the body: into the brain, into the legs and into the arms. Blood returns to the heart by travelling through veins.

Before travelling to the rest of the body, the blood must first travel through the lungs. There, the blood loses all of the carbon dioxide it has collected during its journey. The carbon dioxide is replaced with oxygen, which is then transported to different parts of the body.

The circulatory system is important to our bodies. It transports oxygen and nutrients to the body's cells and tissues. At the same time, it transports carbon dioxide and other harmful substances away from the cells and tissues.