Breathe in… Breathe out… When you breathe, you move air in and out of your lungs. The exchange of oxygen and carbon dioxide gases is called respiration.
External respiration is the exchange of gases in the lungs. Oxygen moves into the blood and carbon dioxide moves out of the blood. Internal respiration is the exchange of gases in your body’s tissues. Blood that is rich with oxygen travels to all parts of the body to exchange gases with other body tissues. Oxygen passes into the tissues from the blood and carbon dioxide passes from the tissues into the blood. The blood with the carbon dioxide then returns to your lungs for external respiration.
When we breathe we exhale and inhale. Both actions are controlled by our diaphragm. When we inhale, our diaphragm contracts, pulling downwards and enlarging our chest. When we exhale, the diaphragm relaxes making the chest area smaller. When your chest area increases in size it reduces the pressure inside your lungs. Air can then move inward towards your lungs. When the pressure in the chest rises, the air in the lungs flows outward.