What is "respiration"?

What is "respiration"?

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...

Respiration is the exchange between oxygen and CO2 in the body. However, it's important to know that it occurs on two levels. There's macro respiration which is when you breath in air which is a little less than 21% oxygen, and then you extract about 4% of that down to about 16%. And when it comes out it contains a lot of CO2. On the cellular level there's respiration that goes on where the oxygen is burned in the process of metabolism, and in burning you've got to have three things: oxygen, fuel, and in the case of the body, glucose and certain fatty acids. You also have to have heat and in exchange for that, you have to have fuel. But when the body's smoke is CO2, and the smoke builds up, it kills you. So respiration serves not only to extract oxygen, but to eliminate CO2. The respiration that occurs at the cellular level has to match the macro level, it is involved in those two aspects.