Body Systems Here we take a brief tour through each of the body’s major systems — such as the heart, lungs, brain, and more. You’ll learn the main role each system plays in keeping the body alive and working together in balance. Video 1: Intro to Body Systems Quiz 2: Intro to Body Systems Video 2: The Cardiovascular System Quiz 2: The Cardiovascular System Video 3: The Respiratory System Quiz 3: The Respiratory System Video 4: The Digestive System Quiz 4: The Digestive System Video 5: The Renal System Quiz 5: The Renal System Back