The body needs oxygen to get rid of hydrogen ions at the end of the electron transport chain. Therefore we must constantly replace the oxygen as we get rid of it in the form of water. Also, we need to get rid of CO2, which form carbonic acid in solution. 1 State the difference between breathing and cell respiration. Breathing is the ventilation of the lungs by negative pressure.
Air then flows into the lungs from the higher pressure environment outside the body.
Both the lungs and heart can bet stronger and larger with use. A characteristic of this would be ability to exercise strenuously without loss of breath and quick return to resting heart rate after exercise. Explain how and why breathing rate varies with exercise. Why- exercise means increased metabolic action, and so decreased oxygen concentration and increased carbon dioxide concentration. The body needs to get more oxygen and get rid of CO2 faster, so it increases breathing rate.