Introduction to the Cardiovascular System The cardiovascular system is like the body's delivery and waste removal service. It's made up of the heart (the pump) and a network of tubes called arteries, veins, and capillaries. The blood inside these tubes is constantly circulated throughout the body. Even a developing baby needs this system to survive. The heart starts beating very early in development, even before other major organs are fully formed. The cardiovascular system's main job is to keep the body's internal environment stable (homeostasis). It does this by constantly moving blood through tiny capillaries that reach every single cell. It's in these tiny capillaries that the real magic happens: Delivery: Nutrients and other important materials are delivered from the blood into the fluid surrounding the cells. Waste Removal: Waste products from the cells are picked up by the blood to be carried away. The body has many ways of controlling this system...