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Hello everyone, and welcome back to part two of our four-part video series on nutrition.

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Last time, we talked about the digestive system, and how food goes through our digestive tract

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and gives us energy. Today, we'll be exploring how we breathe and what makes our lungs work.

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The body needs oxygen to survive, so the respiratory system works to keep our muscles

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functioning. Without the respiratory system, we wouldn't be able to move or think at all.

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I want us to try something. Put your hand on your chest and on the count of three we're going to

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take a deep breath in and let it out. Ready? One, two, three. Inhale and exhale. Did you feel that?

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Did your chest rise and fall? Did you breathe in and exhale through your nose and your mouth?

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I'm sure you did all of that and even more than you know. Let's take a journey through the

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respiratory system with our friend Ms. Frizzle and her students to learn more about how breathing

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works and what it does for our bodies. It all begins with the breath. Even though we don't

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think about it, breathing is incredibly important to our entire bodies. Our bodies need to absorb

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oxygen in order for our muscles to function, which keeps our legs moving, heart pumping,

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and brains working. When you breathe through your mouth or nose, air enters your body.

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From there, oxygen is transported through the trachea, a long rigid tube which is in your neck

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that connects the mouth to two bronchi. Bronchi are two tubes that connect the trachea to the

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lungs. The lungs are the largest part of the respiratory system. Imagine them being two big

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bags that fill up with air when we inhale and deflate when we exhale. But how do the bags fill

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up? With help from the diaphragm. The diaphragm is a dome-shaped muscle underneath the lungs.

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When it contracts, it causes air to be pulled into our lungs, and when it relaxes,

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It helps us push out waste, or carbon dioxide.

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While the diaphragm does its job, the bronchioles are also hard at work.

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Bronchioles are small tubes inside the lungs.

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Inside these bronchioles are tiny sacs called alveoli, which take the air we breathe and help them pass into the bloodstream.

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The bloodstream then carries it all around the body, taking it to muscles that need oxygen.

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Our muscles absorb the oxygen and then excrete carbon dioxide.

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The alveoli do an exchange.

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trading the oxygen for the carbon dioxide which is expelled as a gas when we breathe out. And to

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think this all happens as fast as you can breathe. That's why it's important that we make sure we

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bring in good air into our bodies which keeps our lungs and the rest of our respiratory system

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healthy. Be sure to get outside and get some fresh air daily if you can. I'm sure you already do

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without even thinking about it. Way to go! I hope you learned something new today and that you'll

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take time out of your day to just breathe. Think about how air works its way through your body.

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Get outside and see if you can feel the difference fresh air can truly make.

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And that's all for today. Keep an eye out for part three where we'll connect the respiratory

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system to the circulatory system. Until next time!