b'Respiratory SystemChapter hapterThe human body is made up of millions of tiny cells.All cells need oxygen to function. The human body Average Respiratory Rateneeds a constant supply of oxygen for survival. (Breaths per minute) When you breathe in, air enters and fills the lungs.Adult16-20The oxygen in the air is transferred to the blood.Child16-25The oxygen is transported through blood vessels into the cells by the pumping action of the heart. Infant25-40 The same system removes carbon dioxide. Carbon dioxide is transferred from the blood to the lungs.When you breathe out, air is forced from the lungs, removingcarbon dioxide and other waste gases.The air you breatheIN:Oxygen 21%Carbon Dioxide (traces)Nitrogen 79%When you breathe in, your diaphragm and chest muscles contract and the lungs expand, sucking in air.The air you breathe OUT:Oxygen 17%Carbon Dioxide 4%Nitrogen 79%When you breathe out, your diaphragm and chest muscles relax, squeezing air out.How Your Body Works 21'