Cardiovascular System T he cardiovascular system includes the heart and the blood vessels. The heart pumps blood, and the blood vessels channel and deliver it throughout the body.
Arteries carry blood filled with nutrients away from the heart to all parts of the body.
Arteries are thick-walled tubes with a circular covering of yellow, elastic fibers, which contain a filling of muscle that absorbs the tremendous pressure wave of a heartbeat and slows the blood down. T his pressure can be felt in the arm and wrist - it is the pulse. Eventually arteries divide into smaller arterioles and then into even smaller capillaries, the smallest of all blood vessels. Here, in every tissue of every organ, blood's work is done when it gives up what the cells need and takes away the waste products that they don't need. Now the river comparison really does apply.