Every cell in the body must have oxygen at all times to survive. The cells must also get rid of their carbon dioxide waste. That is the job of the respiratory system.
There are four functional parts to respiration.
1) Pulmonary Ventilation – Bringing oxygen into the lungs and carbon dioxide out of the lungs.
2) Transport of Respiratory Gases – Moving oxygen through the bloodstream from the lungs to all the cells of the body and carbon dioxide from the cells back to the lungs.
3) External Respiration – Exchanging oxygen for carbon dioxide in the capillaries lining the tiny alveoli inside the lungs.
4) Internal Respiration – Exchanging oxygen for carbon dioxide from the capillaries across to the cells.
