What is the "respiratory system"?

What is the "respiratory system"?

Richard Sheldon (Medical Advisor to the CA State Respiratory Care Board) gives expert video advice on: How is a pulmonologist different from other doctors?; What is the difference between the nasal cavity and the sinuses? and more...

The respiratory system is the part of the body that deals with the exchange of oxygen and CO2. It starts off with the nose. It goes back to the nasal cavity, down through the sinuses, turns the corner, goes down through the pharynx, behind the tongue, to the voice box, into the trachea, and then to the right and left main stem bronchi where the divisions go to the right and left lung, down through smaller and smaller tubes, if you will, to where it gets to the alveoli which are little tiny sacs. There are about three million of them in a normal lung, and that's where exchanging oxygen with CO2 takes place. You may like to think of the lower portion of the respiratory tree as like a real tree, only turned upside down, with the trunk being the trachea. Then branches, until you get way out to the end and there you have the little fine twigs, which are the bronchioles. And then they divide into conducting airways and then, finally, to the alveoli which might, in that analogy, be the leaves of the tree.