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What Really Tells Your Lungs to Speed Up

6th grade nonfiction passage about how breathing is controlled: 263 words, seven questions, an answer key and vocabulary.

6th grade nonfiction how breathing is controlled 263 words

What Really Tells Your Lungs to Speed Up

You do not decide to breathe in the same way that you decide to wave. Day and night, awake or asleep, your body keeps the air moving without any orders from you. So who is in charge?

The control center sits in the lower part of the brain, in a region called the brainstem. It sends signals to the diaphragm, the large, dome-shaped muscle under the lungs, and to the muscles between the ribs. Each time they tighten, your chest expands and air flows in. When they relax, air flows out.

What sets the pace is mostly not a shortage of oxygen, as many people guess. It is carbon dioxide. Every cell in your body makes carbon dioxide as a waste product while it uses oxygen for energy. The waste travels in the blood to the lungs, where it is breathed out. Sensors in the brain and in large blood vessels keep track of how much carbon dioxide is present. When the level starts to rise, they tell the brainstem to speed up.

That explains what happens when you run. Working muscles produce much more carbon dioxide, the level climbs, and your breathing becomes deeper and faster until the extra is cleared away. After you rest, the level falls and your breathing settles down again.

It also explains why you can hold your breath for only a short time. As carbon dioxide builds up, the urge to breathe grows stronger and stronger. That strong signal is a protective feature, which is one reason people should never stretch their limits when they swim.

Questions

  1. Where is the control center for breathing? in the text

  2. What is the diaphragm? in the text

  3. What gas mostly sets the pace of your breathing? in the text

  4. What happens to the carbon dioxide that the cells make? in the text

  5. Why does your breathing speed up when you run? think about it

  6. Why does the urge to breathe grow stronger when you hold your breath? think about it

  7. Why is the strong urge to breathe a protective feature? think about it

Words to know

brainstem
the part of the brain that controls basic jobs like breathing
diaphragm
the big muscle under the lungs that helps you breathe
carbon dioxide
a gas that body cells make as waste
oxygen
a gas in the air that body cells need to make energy
sensors
tiny parts that notice changes and send messages
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One passage, three levels

The same topic and facts written three ways, so a mixed class can read and talk about one text. Each group’s sheet shows only a shape; the key says which is which.

● Easier · 248 words · Flesch-Kincaid grade 3

You do not choose to breathe the way you choose to wave. Day and night, awake or asleep, your body keeps air moving. You do not give orders. So who is in charge?

The control center is in the lower part of the brain. It is called the brainstem. It sends signals to the diaphragm. That is the big, dome-shaped muscle under the lungs. It also signals the muscles between the ribs. When they tighten, your chest gets bigger and air comes in. When they relax, air goes out.

What sets the pace? Many people guess it is a lack of oxygen. But it is mostly carbon dioxide. Every cell in your body makes carbon dioxide as waste while it uses oxygen. The waste goes in the blood to the lungs. Then you breathe it out. Sensors in the brain and in big blood vessels check how much carbon dioxide there is. When the level goes up, they tell the brainstem to speed up.

That is what happens when you run. Your working muscles make much more carbon dioxide. The level goes up. So you breathe deeper and faster until the extra is gone. When you rest, the level goes down, and your breathing calms.

It also shows why you can hold your breath for only a short time. Carbon dioxide builds up. The urge to breathe gets stronger. That strong urge protects you. This is one reason people should never push their limits when they swim.

▲ This passage · 263 words · Flesch-Kincaid grade 5.8

You do not decide to breathe in the same way that you decide to wave. Day and night, awake or asleep, your body keeps the air moving without any orders from you. So who is in charge?

The control center sits in the lower part of the brain, in a region called the brainstem. It sends signals to the diaphragm, the large, dome-shaped muscle under the lungs, and to the muscles between the ribs. Each time they tighten, your chest expands and air flows in. When they relax, air flows out.

What sets the pace is mostly not a shortage of oxygen, as many people guess. It is carbon dioxide. Every cell in your body makes carbon dioxide as a waste product while it uses oxygen for energy. The waste travels in the blood to the lungs, where it is breathed out. Sensors in the brain and in large blood vessels keep track of how much carbon dioxide is present. When the level starts to rise, they tell the brainstem to speed up.

That explains what happens when you run. Working muscles produce much more carbon dioxide, the level climbs, and your breathing becomes deeper and faster until the extra is cleared away. After you rest, the level falls and your breathing settles down again.

It also explains why you can hold your breath for only a short time. As carbon dioxide builds up, the urge to breathe grows stronger and stronger. That strong signal is a protective feature, which is one reason people should never stretch their limits when they swim.

■ Harder · 273 words · Flesch-Kincaid grade 7.6

You do not decide to breathe in the same deliberate way that you decide to wave to a friend. Day and night, whether you are awake or asleep, your body keeps the air moving without any instructions from you. So what, exactly, is in charge?

The control center is located in the lower part of the brain, in a region called the brainstem. It transmits signals to the diaphragm, the large, dome-shaped muscle beneath the lungs, and to the muscles between the ribs. Each time these muscles tighten, your chest expands and air rushes in. When they relax, air flows back out.

What determines the pace is generally not a shortage of oxygen, as many people suppose. It is carbon dioxide. Every cell in your body produces carbon dioxide as a waste product while it uses oxygen to release energy. That waste is carried by the blood to the lungs, where it is exhaled. Sensors in the brain and in large blood vessels continually monitor how much carbon dioxide is present. When the level begins to climb, they instruct the brainstem to accelerate.

This explains what happens when you run. Working muscles generate far more carbon dioxide, the level rises, and your breathing becomes deeper and faster until the surplus has been cleared away. Once you rest, the level falls and your breathing gradually settles.

It also explains why you can hold your breath for only a short time. As carbon dioxide accumulates, the urge to breathe grows steadily stronger. That powerful signal is a protective feature, which is one reason people should never try to stretch their limits when they swim.

Download as one PDF

How to use it

  1. Press Read it big (or B) to put the text on the projector, or Full screen (F) to fill the whole screen.
  2. Ask the questions one at a time and use Show answer when the class has decided. A shows or hides every answer.
  3. Print student copy for the class, or Print with answers for yourself.

Ideas for class

  • Before reading, put brainstem, diaphragm, carbon dioxide, oxygen and sensors on the board with their meanings from the Words to know section and have students predict what the text will be about.
  • Read it aloud once while students follow along, then have them reread it alone or with a partner. At a calm 100 words a minute it takes about 3 minutes to read aloud.
  • Use the Read it big button (or B) to put the text on the projector, and Show answer on one question at a time so the class commits to an answer first.
  • Question 5 asks the reader to infer. Ask students to point to the words in the passage that led them to their answer.
  • Ask students to write one question the passage did not answer, then look for the answer in a book or on a classroom screen.
  • Print the student copy for independent work and keep the answer-key copy for yourself.

Related

Questions

What reading level is "What Really Tells Your Lungs to Speed Up"?

It was written for 6th grade. It has 263 words and works out to a Flesch-Kincaid grade level of about 5.8. That is a formula's estimate from sentence length and syllables, and it is not a Lexile or a guided reading level, so check it against your students.

What do the questions ask?

There are seven. 4 ask for something the text says directly and 3 ask the reader to work something out from clues. Each has an answer in the key, and the answers are written as a teacher would accept them, not as the only possible wording.

How long does it take to read?

About 3 minutes read aloud at 100 words a minute. For a one-minute fluency check, paste it into the fluency timer and use the word count.

Can I print it?

Yes. Print student copy gives the passage, the questions with lines to write on, and the word meanings. Print with answers gives the same page with the answers filled in. Both are made in your browser.

Is this passage from a published book?

No. It was written for Peabody Teach, so there is no book to buy and no login to read it.

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