How Our Lungs Work: Main Processes & Function

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  • 0:02 Your Lungs
  • 1:08 Inhaling
  • 2:45 Exhaling
  • 3:42 Lesson Summary
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Lesson Transcript
Instructor: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

Do you know what happens to the air that you breathe in? Learn how your lungs take in air to supply your body with oxygen and what waste gas is expelled from your lungs when you breathe out.

Your Lungs

Did you ever try to see how long you could hold your breath? The first time you try you might only be able to hold it for about thirty seconds before you feel a need to gasp for more air; but, if you practice, you can train yourself to hold it much longer. In fact, experienced divers can routinely hold their breath for five minutes or more! Of course, no one can hold their breath forever; eventually the body demands a fresh supply of good, clean air to fill up your lungs.

Your lungs are a pair of organs found inside your chest. They carry out a very important function, which is to bring oxygen in and get rid of carbon dioxide. Oxygen is a gas found in air that your cells need to work properly. Carbon dioxide is also a gas, but it's actually a waste product that your cells produce from the work they do. So breathing in, or inhaling, is like bringing necessary supplies into your house and breathing out, or exhaling, is like taking out the trash.


That explains why we breathe, but it doesn't explain how this process of inhaling and exhaling works. Well, it all starts with the diaphragm, which is a wide muscle that lies below the lungs. When your body needs more air, your diaphragm contracts and flattens out. It's kind of like the lungs are part of a carnival ride where the floor drops out below them. When this happens it creates more space in your chest, which acts somewhat like a vacuum sucking air in through your nose and mouth. At the same time your rib cage moves out, which adds even more space for your lungs to expand. The inhaled air passes through tubes and inflates your lungs.

If we go inside of you we see that the branched tubes that carry air into your lungs are called bronchioles. These bronchioles branch out into your lungs like twigs on a tree. The smallest ones are no wider than a strand of your hair. At the end of the bronchioles we find alveoli, which are tiny air sacs. The walls of the alveoli are very thin, so thin that oxygen from the inhaled air can pass through them and enter tiny blood vessels called capillaries that are nearby. Capillaries are so small that blood cells must pass through them single file. These blood cells give the oxygen a ride around the bloodstream and drop it off at any cell in need.

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