Breathing Rate

Breathing rate is controlled mostly by your brain, and brain stem. The brain sends a message to the diaphragm telling it to expand. That message is sent when you breathe in. So deoxyginated blood is rushed to the lungs, when you breathe in, you bring oxygen into the alveoli. The oxygen in there will be exchanged for CO2 in the blood. When you breathe out, you release all the CO2 from your blood back out.