L U N G Breathing air is necessary for keeping humans and many animals alive. And the two parts that are large and in charge when it comes to breathing it is definition the lungs. Your lungs make up one of the largest organs in your body and work with your respiratory system. Locate lung and respiratory system. You have two lung,but they aren’t the same size. The lung on the left side of your bpdy is a bit smaller than the lung on the right. This extra space on the left leaves room for your heart. Your lungs are protected by your rib cage. Beneath the lungs is the diaphragm, a dome-sharped muscle that works with your lungs to allow you to breathe in and breathe out air. Spirometry one of many tests to how well are you breathing? You take a breathe and then blow the air out as fast and long as you cn. These tests can help a doctor find out if someone has asthma.