Our lungs are the primary organs of our respiratory system and they function in the process of breathing. Now, breathing is a simple process of inhaling oxygen and exhaling carbon dioxide. And breathing is also known as ventilation or respiration. Now, this respiration process is not the same thing as cellular respiration that takes place within the individual cells of our body. Cellular respiration is when our cell uses oxygen to produce ATP and produces carbon dioxide as a byproduct. But respiration is simply the breathing process, the process by which we inhale oxygen and we exhale.