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.
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.
So that's how oxygen gets into your body, but how does carbon dioxide get out? Well, that's easy because the process simply goes in reverse. Carbon dioxide that was produced by your body cells gets dumped back into the bloodstream, where it travels around until it finds its way into the tiny capillaries of your lungs. Here, the thin walls of the capillaries allow carbon dioxide to pass into the alveoli. Now this waste gas is in your lungs and ready to be exhaled. To do this, your diaphragm relaxes causing it to bulge up, which pushes air out of your lungs. At the same time your rib cage relaxes making the space in your chest even smaller and forcing even more air out. It looks like the carnival ride is over and it is time for carbon dioxide to exit the ride. The exit ramp is through the bronchioles and out the mouth and nose.
Let's review. Your lungs are a pair of organs found inside your chest. Their job is to bring oxygen in and get rid of carbon dioxide. Your cells need oxygen to work properly, and the only way to get it is by breathing in, or inhaling, air. Carbon dioxide is a waste product produced by your cells. You get rid of it by breathing out, or exhaling.
Your diaphragm is a wide muscle that lies below the lungs. It helps you inhale and exhale. When your body needs more air, your diaphragm contracts and flattens out and your rib cage expands; this sucks air through your nose and mouth. This air passes through bronchioles, which are the branched tubes that carry air into your lungs and into the tiny air sacs of your lungs called alveoli. The alveoli hand off oxygen to your bloodstream through tiny blood vessels called capillaries.
Carbon dioxide leaves the same way oxygen came in. Carbon dioxide produced by your body cells gets dumped back into the capillaries of your blood and passed into the alveoli of the lungs. Now, your diaphragm and your rib cage relax, which pushes air out of your lungs through the bronchioles and out your nose and mouth.
After watching this lesson, you should be able to:
- Define the main function of lungs
- Describe the processes of inhaling oxygen and exhaling carbon dioxide from the lungs
- Recall the different components of the lungs and what they do