External respiration:
When we inhale, we're bringing gasses from our outer surroundings into our interior surroundings, or inside our bodies. We're likewise moving gasses out of our bodies when we breathe out.
Internal respiration:
The air moving into our bodies interfaces with our respiratory surfaces, to be specific the lungs. We retain oxygen from the air we breathe in into our cells, and in the meantime, we discharge and breathe out carbon dioxide out of our bodies. This procedure of gas trade over a respiratory surface is known as inward respiration.
