Breathing

BREATHING; CONSUMING AIR; TAKING AIR INTO AND EXPELLING IT FROM THE LUNGS; BREATHING (OR VENTILATION) IS THE PROCESS OF MOVING AIR INTO AND FROM THE LUNGS TO FACILITATE GAS EXCHANGE WITH THE INTERNAL ENVIRONMENT, MOSTLY TO FLUSH OUT CARBON DIOXIDE AND BRING IN OXYGEN. ALL AEROBIC CREATURES NEED OXYGEN FOR CELLULAR RESPIRATION, WHICH EXTRACTS ENERGY FROM THE REACTION OF OXYGEN WITH MOLECULES DERIVED FROM FOOD AND PRODUCES CARBON DIOXIDE AS A WASTE PRODUCT. BREATHING, OR "EXTERNAL RESPIRATION", BRINGS AIR INTO THE LUNGS WHERE GAS EXCHANGE TAKES PLACE IN THE ALVEOLI THROUGH DIFFUSION. THE BODY'S CIRCULATORY SYSTEM TRANSPORTS THESE GASES TO AND FROM THE CELLS, WHERE "CELLULAR RESPIRATION" TAKES PLACE.