The document summarizes the key components and functions of the respiratory system. It describes how air travels through the nose or mouth into the trachea, which then branches into the bronchi and bronchioles leading to the alveoli in the lungs. The alveoli are where gas exchange occurs, as oxygen passes into the bloodstream while carbon dioxide is removed. Breathing is controlled by the respiratory center in the brain and muscles like the diaphragm and ribs. Disruption of the respiratory system for more than a few minutes can cause tissue damage and ultimately death if normal breathing is not restored.