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The Fist-Sized Filters Beside Your Spine

8th grade nonfiction passage about how the kidneys clean blood: 255 words, six questions, an answer key and vocabulary.

8th grade nonfiction how the kidneys clean blood 255 words

The Fist-Sized Filters Beside Your Spine

Tucked against the back wall of your abdomen, just below the ribs, sit two organs that are each about the size of a fist. They are the kidneys, and they work around the clock as the body's filtration plant, cleaning the blood without ever taking a break.

Blood arrives at each kidney through a large artery. Inside, it passes through about a million tiny filters called nephrons. Each nephron has a knot of microscopic blood vessels that lets water and small dissolved substances squeeze out of the blood, while blood cells and large proteins stay inside. The filtered liquid then travels through a long, narrow tube. Along the way, the body takes back what it needs, such as water, sugars, and useful salts, and returns them to the blood. What is left, the waste and the extra water, becomes urine. Urine flows through tubes called ureters to the bladder, where it is stored until you use the bathroom.

Kidneys do more than clean. They help control how much water is in your body, keep salts and minerals in balance, and release hormones. One of these hormones helps manage blood pressure, and another tells the bone marrow to make red blood cells.

Because the job is so important, kidneys are worth protecting. Drinking enough water, eating a balanced diet without too much salt, and staying active all help. A person can live a healthy life with only one working kidney, which is why some people choose to donate one to a patient whose kidneys have failed.

Questions

  1. Where are the kidneys located? in the text

  2. What are nephrons? in the text

  3. What stays in the blood during filtering? in the text

  4. What becomes urine? in the text

  5. Why is it possible to donate a kidney and stay healthy? think about it

  6. What is one job of the kidneys besides cleaning the blood? in the text

Words to know

filtration
the process of straining out unwanted things
nephrons
the tiny filtering units inside a kidney
ureters
tubes that carry urine from the kidneys to the bladder
hormones
chemical messengers made in the body
artery
a blood vessel that carries blood away from the heart
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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 · 229 words · Flesch-Kincaid grade 2.7

Two organs sit against the back wall of your belly, just below your ribs. Each one is about the size of a fist. They are your kidneys. They work all day and night to clean your blood.

Blood comes to each kidney through a big artery. Inside, it flows through about a million tiny filters. These are called nephrons. Each nephron has a knot of very small blood vessels. Water and small dissolved things squeeze out of the blood. Blood cells and big proteins stay in. The liquid that came out then moves through a long, thin tube. On the way, the body takes back what it needs. This includes water, sugars, and useful salts. What is left is waste and extra water. That becomes urine. Urine goes through tubes called ureters to the bladder. It waits there until you use the bathroom.

Kidneys do more than clean. They help control how much water is in your body. They keep salts and minerals in balance. They also make hormones. One helps control blood pressure. Another tells the bone marrow to make red blood cells.

Kidneys do a big job, so take care of them. Drink enough water. Eat balanced meals without too much salt. Stay active. A person can be healthy with just one kidney. That is why some people give one to a patient whose kidneys have failed.

▲ This passage · 255 words · Flesch-Kincaid grade 7.4

Tucked against the back wall of your abdomen, just below the ribs, sit two organs that are each about the size of a fist. They are the kidneys, and they work around the clock as the body's filtration plant, cleaning the blood without ever taking a break.

Blood arrives at each kidney through a large artery. Inside, it passes through about a million tiny filters called nephrons. Each nephron has a knot of microscopic blood vessels that lets water and small dissolved substances squeeze out of the blood, while blood cells and large proteins stay inside. The filtered liquid then travels through a long, narrow tube. Along the way, the body takes back what it needs, such as water, sugars, and useful salts, and returns them to the blood. What is left, the waste and the extra water, becomes urine. Urine flows through tubes called ureters to the bladder, where it is stored until you use the bathroom.

Kidneys do more than clean. They help control how much water is in your body, keep salts and minerals in balance, and release hormones. One of these hormones helps manage blood pressure, and another tells the bone marrow to make red blood cells.

Because the job is so important, kidneys are worth protecting. Drinking enough water, eating a balanced diet without too much salt, and staying active all help. A person can live a healthy life with only one working kidney, which is why some people choose to donate one to a patient whose kidneys have failed.

■ Harder · 258 words · Flesch-Kincaid grade 9.5

Wedged against the rear wall of your abdomen, just beneath the ribs, lie two organs that are each roughly the size of a fist. These are the kidneys, and they labor around the clock as the body's filtration plant, cleansing the blood without ever pausing.

Blood reaches each kidney by way of a large artery. Inside, it streams through about a million microscopic filters known as nephrons. Every nephron contains a knot of tiny blood vessels that permits water and small dissolved substances to squeeze out of the blood, while blood cells and large proteins remain behind. The filtered liquid then passes along a long, narrow tube, and during that journey the body reclaims what it requires, including water, sugars, and valuable salts, returning them to the bloodstream. What remains, the waste together with surplus water, becomes urine. Urine flows through tubes called ureters into the bladder, where it is stored until you use the bathroom.

The kidneys accomplish far more than cleaning. They help regulate how much water your body holds, maintain a balance of salts and minerals, and release hormones. One of these hormones helps manage blood pressure, while another instructs the bone marrow to produce red blood cells.

Because the work is so vital, the kidneys deserve protection. Drinking enough water, eating a balanced diet that is not overloaded with salt, and staying physically active all contribute. A person can lead a healthy life with only one working kidney, which is why some individuals choose to donate one to a patient whose kidneys have failed.

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 filtration, nephrons, ureters, hormones and artery 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 "The Fist-Sized Filters Beside Your Spine"?

It was written for 8th grade. It has 255 words and works out to a Flesch-Kincaid grade level of about 7.4. 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 six. 5 ask for something the text says directly and 1 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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