This blood circulation diagram depicts the cardiovascular system, which transports nutrients and oxygen to all cells in the body. It is made up of the heart and the blood vessels that run throughout the body. The arteries carry blood away from the heart, while the veins return it. The blood vessel system resembles a tree: The "trunk," or main artery (aorta), divides into large arteries that branch into smaller and smaller vessels. The capillary network is a network of tiny vessels that connects the smallest arteries. There are two blood circulatory systems in the human body that are linked: The systemic circulation delivers blood to organs, tissues, and cells, allowing them to receive oxygen and nutrients.
