the air goes in and out, like breathing
The process of gas exchange between the alveoli and the blood by the process of difusion. Some of the air you just inhaled will enter the bloodstream.
Movement of the oxygenated blood, moves it from your lungs to the cells of your body and takes CO2 from cells in your body and returns it to the lungs to be exhaled.
the gas exchange occurring between the blood and systemic tissue cells.