The function of the respiratory system is to take in and excrete materials. You breathe in oxygen rich air and you breathe out carbon dioxide rich air. When you breathe in the oxygen-rich air goes through the nasal cavity where dust and dirt is swept up by tiny hairs. The air goes through the pharynx and into the larynx. In the larynx is your voice box. When you get laryngitis, you lose your voice. From the larynx, the air goes into the trachea. The trachea splits off into two bronchi (one bronchus). The bronchi split into bronchioles which have alveoli on them. The alveoli are surrounded by capillaries, and the capillaries and the alveoli trade materials. The carbon dioxide rich air that has just entered the alveoli now goes back up the same route the oxygen rich air came in. You have now breathed out. Then, the whole process starts again when you breathe in.
The structures of the respiratory system are:
I think that it's amazing that all these things are happening in your respiratory system so fast. I'm a swimmer and I concentrate on breathing a lot. When I take a breath of air and hold it and blow out while I'm underwater, it happens so fast that it isn't recognizable that so much is going on in just one breath. It's so amazing how all these systems work together to form one person.