The Respiratory System
The respiratory system is the group of tissues and organs in your body that allow you to breathe. This system includes your airways, your lungs, and the blood vessels and muscles attached to them that work together so you can breathe. The respiratory system’s main function is to supply oxygen to all the parts of your body. It does this through breathing: inhaling oxygen-rich air and exhaling air filled with carbon dioxide, which is a waste gas.
This is how the respiratory system works: first you breathe air in through your nose and mouth, which wet and warm the air so it won't irritate your lungs. Then the air travels through your voice box, down your windpipe, and though two bronchii (bronchial tubes) into your lungs. Cilia, tiny mucous-covered hairs, in your airways trap foreign particles and germs to filter the air that you breathe. You then cough or sneeze the particles out of your body.
The diaphragm, abdominal muscles, and other muscles help your lungs expand and contract so you can inhale and exhale. When you inhale, the air goes through the bronchii in your lungs to blood vessels that connect to veins and arteries. These veins and arteries carry the blood throughout your body. When you exhale, the carbon dioxide goes out the same way, exiting your body through your nose and mouth. If you can't breathe or can't breathe well, your body won’t receive enough oxygen to keep it running, and it will also be poisoned by the carbon dioxide that is building up in your blood with nowhere to go.
Fun Fact: You breathe in and out anywhere from 15 to 25 times per minute!