Human Body: How Do the Lungs Work?

Each time a person breathes, air enters the nose and airways.  It goes through the trachea to the lungs.  Then, the air goes through the bronchi to the bronchioles which spread out like the branches of a tree.  From there, millions of very small airways carry the air to tiny air sacs called alveoli.  From these tiny air sacs, the air is absorbed into blood vessels.

• In the normal lung, the air has no problem getting through to the air sacs because the muscles that wrap around the airways are very loose and thin.  This gives the airways plenty of room to open up.
• When the airways are open, it’s easy for air to move in and out of the tiny air sacs.  In other words...it’s easy to breathe!  

WHEN THERE IS A PROBLEM

• The airways in people with asthma, for example, tend to react strongly to certain substances like dust, mold, pet dander, cold air or even to stress by swelling or becoming inflamed.
• Once the swelling begins, the body first reacts by producing more mucus.  Then, the muscles that wrap around the airways tighten upon contract. 
• The airways become smaller from the swelling and the tightening of the muscles and end up getting clogged with all that extra mucus.
• Sometimes there is so much mucus that it forms into sticky plugs!
• The swollen and clogged airways make it very hard to move air in and out of the lungs, so it’s difficult to breathe!!!