The circulatory system of a water treatment plant is based on pumps, closed tubular structures or pipes, and valves. Much like water is moved through a water treatment plant, the human body has a strong central pump , pipes of various sizes (blood vessels), and valves (in both the heart and veins) that work to move blood (including nutrients, gases, and wastes) through the body.

In this lesson, you will learn about the heart's structure and function. You will examine its role in circulating blood throughout the body. You will also learn about the blood vessels that lead to and from the heart that help to circulate this blood.

In this lesson, you will explore the following essential questions:

• What are the major structures and functions of the circulatory system?
• How do the principal structures of the circulatory system move blood through the body?