ou usually don't even notice it, but twelve to twenty times per minute, day after day, you breathe -- thanks to your body's respiratory system. Your lungs expand and contract, supplying life-sustaining oxygen to your body and removing from it, a waste product called carbon dioxide.
The Act of Breathing
Breathing starts at the nose and mouth. You inhale air into your nose or mouth, and it travels down the back of your throat and into your windpipe, or trachea. Your trachea then divides into air passages called bronchial tubes.
For your lungs to perform their best, these airways need to be open during inhalation and exhalation and free from inflammation or swelling and excess or abnormal amounts of mucus.
The LungsAs the bronchial tubes pass through the lungs, they divide into smaller air passages called bronchioles. The bronchioles end in tiny balloon-like air sacs called alveoli. Your body has over 300 million alveoli.
The alveoli are surrounded by a mesh of tiny blood vessels called capillaries. Here, oxygen from the inhaled air passes through the alveoli walls and into the blood.
After absorbing oxygen, the blood leaves the lungs and is carried to your heart. Your heart then pumps it through your body to provide oxygen to the cells of your tissues and organs.
As the cells use the oxygen, carbon dioxide is produced and absorbed into the blood. Your blood then carries the carbon dioxide back to your lungs, where it is removed from the body when you exhale.