The structure that transports oxygen-rich blood away from the heart is called the artery. Specifically, the largest artery in the human body is the aorta, which branches off to deliver oxygenated blood to various parts of the body, ensuring that essential nutrients and oxygen reach tissues. The muscular walls of arteries help maintain blood pressure and enable them to withstand the high force of blood pumped from the heart. Arteries play a crucial role in the circulatory system, supporting overall cardiovascular health and functionality.