Ch 33 The Circulatory System Study Guide - In this lesson, learn about the circulatory system and how it functions within your body. Explore how the heart and blood vessels help the circulatory system move blood through the body. 2017-12-03. If you can make dinner, you can convert units in the metric system. It's that easy! In this lesson, you'll learn about the three key things you'll need to perform conversions. 2017-03-28.