Changes
[[Image:Lungs.jpg|240px|thumb|Bronchi and Lungs]]
The human '''respiratory system''' is responsible for the exchange of [[carbon]] dioxide (CO<sub>2,</sub>) and [[oxygen]] (O<sub>2</sub>). Oxygen is essential in the production of adenosine triphosphate (ATP)—the nucleotide responsible for cell metabolism the "fuel" of the cell— by the mitochondria. [[Human]] beings cannot live without a properly functioning respiratory system unless some sort of mechanical intervention (e.g. ventilator, heart-lung bypass) is implemented.
