How Your Body Uses Oxygen Oxygen is a gas that your body uses for energy. It is needed by your body cells to keep them alive. Being able to move and think require your body to have oxygen. This handout will talk about how your body uses oxygen. How do you get oxygen in your body? Oxygen is found in the air around you, along with nitrogen and other gases. When you take a breath, air goes in through your nose and mouth. It passes through your trachea or windpipe and into airways called bronchi (BRAWNki) in your lungs. The airways branch off into smaller and smaller openings. At the end of the openings are alveoli (al-VEE-o-lie), or tiny air sacs. The air bounces around in these tiny air sacs and blood cells in the very small blood vessels around these air sacs pick up oxygen. These very small blood vessels are called capillaries (KAP-e- ler-ees). Capillaries connect your arteries and veins. They are found all over your body. It is in these small blood vessels in your lungs that oxygen gets into your blood. This oxygen rich blood then goes back into the left side of your heart where it gets pumped out to all parts of your body through your arteries. More on next page  Learn more about your health care. © Copyright 2006 - March 5, 2013. The Ohio State University Wexner Medical Center - Upon request all patient education handouts are available in other formats for people with special hearing, vision and language needs, call (614) 293-3191. Page 2 What happens when the oxygen is carried to the cells? Through the rest of your body, these small blood vessels or capillaries are where oxygen is dropped off to your cells and waste products, like carbon dioxide are picked up. The waste products are then carried in your blood through your veins back to the right side of your heart. When the blood gets back to your heart, there is very little oxygen left in it, and there are larger amounts of waste products. The blood goes into the right side of your heart and then gets pumped back into your lungs. The gray area in the picture shows this. The waste gases, like carbon dioxide, are passed from the blood through the capillaries into the air sacs. They are then breathed out through your lungs while more oxygen is being picked up by your blood cells. This air exchange happens quickly and often. There is a chemical in your blood called hemoglobin (HE-mo-glow-bin). This is what picks up and carries the oxygen in your blood. When there is oxygen, the hemoglobin turns bright red in color. As the oxygen is dropped off to the cells, the hemoglobin turns a darker red or purple color. This color change is what is used during a pulse oximeter reading to give your oxygen level.  Talk to your doctor or others on your health care team if you have any questions. You may request more written information from the Library for Health Information at (614) 293-3707 or email: [email protected].