Inside the Human Body

Students study two important body systems, the digestive and urinary systems, through a variety of informational texts and hands-on projects.

Unit Summary

As part of the upgrade to Fishtank Plus, this unit was revised in March 2021. See which texts and materials have changed as part of the revision in this guide to our 2nd Grade text adjustments. If you are looking for the previous version of this unit, you can find it in our archives here.

In this unit, students study two important body systems in depth, the digestive and urinary systems. Students will be challenged to think about how the human body is a miraculous machine, in particular how the digestive and urinary systems are crucial for survival, by deeply analyzing and exploring the steps in both systems. After learning about how both systems function, students will learn about nutrition and how what we eat can either positively or negatively impact the way our body functions. Students will explore what it means to eat a well-balanced meal and how added sugars harm their bodies. It is our hope that this unit will help students build a deeper understanding of the human body and how the decisions we make daily, especially with food, can either help or harm us.

This unit builds onto skills learned in Units 1 through 4, and it is assumed that students are inquisitive consumers of text, asking and answering questions about the content they are learning as a way to deepen understanding of new material. The core text for this unit, The First Human Body Encyclopedia, was chosen because of its wide range of text features and content. While reading the encyclopedia, students should be challenged to think about how the different text features help them locate information and also how the images and diagrams help them clarify the information they are learning. Students should also be challenged to think about the connection between scientific ideas, using language that refers to cause and effect and sequence, particularly when explaining how different systems function. Finally, the study of a text or section’s main topic will continue to spiral throughout this unit. Students should constantly be stopping and asking themselves, “What was the main topic of this section and how do I know?”

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Texts and Materials

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Core Materials

Supporting Materials

See Text Selection Rationale


This assessment accompanies this unit and should be given on the suggested assessment day or after completing the unit.

Unit Prep

Essential Questions


  • What makes the human body amazing?
    The human body is amazing because all of its systems work together to keep you healthy. Your digestive system helps you get all the important nutrients you need to keep your body full of energy. Then it gets rid of what it does not need. This happens automatically—you never even think about it! The urinary system also does this. It takes nutrients to your blood, and then sends excess chemicals and water out of your body through urine. You need to eat nutritious foods to keep your amazing body functioning well.
  • Why is the digestive system important?
    The digestive system is important because it is how you get important nutrients, vitamins, and minerals into your body. After swallowing food, it goes down your esophagus and into your stomach. Your stomach churns the food and protein gets absorbed into your body. The rest of the food travels to your intestines, where digested food gets absorbed into your blood and taken away. The excess food leaves your body as poop. The digestive system helps fuel your body and give you energy you need to play, grow, and sleep!
  • How does food keep our body healthy?
    Food gives us important nutrients, vitamins, and minerals that help our body stay healthy. Nutrients, like carbohydrates, protein, and fat give us the energy to breathe, move, fight germs, and stay warm. Carbohydrates are our main supply of energy. It is important to eat starchy foods, like bread and pasta, to give you long-lasting energy. Even though sweet foods have carbohydrates, the energy you get from them is used up really quickly! Protein gives you energy, too. It helps to build and repair your muscles, skin, brain, and blood. You can get protein from eggs, meat, or nuts. Fat is important to keep you warm and give you energy! Vitamins and minerals also keep your body healthy. Eating enough of them helps your skin to heal, helps you see in the dark, or helps your brain work well. Eating a balanced, nutritious meal—and drinking lots of water—will help you keep your body healthy!

Foundational Skills

Phonics and Word Recognition Focus Areas

  • Use known spelling-sound correspondences when reading one-syllable and two-syllable words
  • Use known spelling-sound correspondences when reading multisyllabic words

The core texts in this unit include many domain-specific words that students will need to decode (e.g., nutrients, digestion, intestine, enzymes, etc.). At this point, students should be fluid in identifying known spelling-sound correspondences in one-syllable and two-syllable words; however, they may struggle to decode longer multisyllabic words. When prepping for a lesson and internalizing the text complexity of a particular text, we suggest identifying multisyllabic words that may be challenging for students. Look at all of the words to see if there are any patterns. Are most of the words closed syllables? Open syllables? R-controlled? If so, include a quick teaching point to focus on strategies students can use to tackle the multisyllabic words in the text. If there are no patterns, pick a few words to model with students and review how to use syllabication to tackle challenging words. During reading, circulate and provide additional teaching and guidance on syllabication.

Fluency Focus Areas

  • Readers read with expression and volume to match interpretation of the passage
  • Readers use proper intonation to show interpretation of the passage
  • Readers reread in order to confirm or self-correct word recognition and understanding

Like prior units, the main fluency focus of this unit is on reading an informational text with the right expression and intonation to show interpretation of the passage. This includes knowing how to read different text features to highlight the feature's purpose and rereading and self-correcting in order to figure out the meaning of domain-specific, multisyllabic, or tricky words. This unit includes both Read Aloud and shared reading texts; therefore, students will have a chance to hear multiple examples of fluent reading while also having ample time to practice reading fluently on their own.

Writing Focus Areas


Sentence-Level Focus Areas

  • Expanding sentences using question words

At this point in the year, students have learned how to determine what makes a sentence; correct run-on sentences; expand sentences using “because,” “but,” or “so”; combine simple sentences; and use subordinating conjunctions to introduce dependent clauses at the beginning of a sentence. Practicing sentence expansion activities allow students to anticipate what a reader needs to know and to provide that information, while also checking comprehension. Sentence expansion also helps students develop the ability to summarize and craft more complex sentences.

Paragraph-Level Focus Areas

  • Brainstorming and relating details; filling in an Single Paragraph Outline as a class

Though students have used the Single Paragraph Outline during their writing projects throughout the year, this is the first time students will be working on writing paragraphs to summarize what they have learned. Students will begin that work as a whole class, and then will shift to writing paragraphs independently, with a focus on generating topic sentences from given details.

Opinion Writing Focus Areas

  • Generate strong opinions

In Unit 3, students generated evidence and brainstormed strong topic sentences that are supported by this evidence. In this unit, students will continue to practice using strong evidence to support an opinion. This time, their opinion will be informed by a new nonfiction text related to the content knowledge they have accumulated during the unit.




absorb automatically chemical contract digestive energy enzymes encyclopedia excess label nutritious nutrients physical saliva shallow thirst urine villi vomit waste


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Related Teacher Tools:

Content Knowledge and Connections


  • Explain that many important systems in the human body work together to help your body function.
  • Identify important components of the digestive system and their function.
  • Describe the process of nourishing the body from the time food is taken into the mouth until waste is removed from the body.
  • Identify different components of the excretory system and their functions.
  • Explain the importance of vitamins and minerals to the body.

Lesson Map



Explain what they already know about the human body, and brainstorm what they want to know by asking and answering questions in a class discussion.


  • Me and My Amazing Body


Identify and explain the different parts of the human body and why each part is important by identifying the main topic of sections of a text.


  • First Human Body pp. 10 – 11




Explain what makes an encyclopedia unique and how to use an encyclopedia to answer questions about the human body by knowing and using various text features and illustrations to locate key facts and information.


  • First Human Body pp. 82 – 85



Describe how digestion happens and the role of teeth in the digestive process by describing the connection between a series of scientific ideas or concepts.


  • First Human Body pp. 86 – 87



Describe what happens once food enters your mouth by describing the connection between a series of scientific ideas or concepts.


  • First Human Body pp. 88 – 89



Describe what happens after food leaves the stomach by describing the connection between a series of scientific ideas or concepts.


  • First Human Body



Construct better and more informative sentences by using question words to add more details.


  • The Digestive System pp. 22 – 29



Explain what things can go wrong during digestion and why by describing the connection between a series of scientific ideas or concepts.


3 days


  • The Digestive System

  • First Human Body




Explain and reteach what happens to a piece of food as it travels through the digestive system by writing a well-structured paragraph that describes the connection between a series of scientific ideas or concepts.


  • First Human Body pp. 90 – 91



Describe what happens in the urinary system by describing the connection between a series of scientific ideas or concepts.


  • First Human Body pp. 92 – 93



Describe how the bladder works and why by describing the connection between a series of scientific ideas or concepts.


2 days


  • First Human Body


Write a paragraph and create a poster that describes the urinary system by writing a well-structured paragraph that describes the connection between scientific concepts.


  • Good Enough to Eat


Describe carbohydrates, protein, fat, and vitamins and minerals and why they are important for keeping your body healthy by describing the connection between a series of scientific ideas or concepts.


  • First Human Body pp. 106 – 107




Explain why the author says, “You need a variety of foods to keep your body in peak working condition” by describing the connection between a series of scientific ideas or concepts.


  • “Read the Label Youth Outreach Materials”


Explain the different parts of a food label and explain if a food is nutritious by analyzing and explaining specific images in a text.


2 days


  • Glue

  • Scissors

  • Grocery store circulars, magazines, pictures of food (for collaging)

  • Plate Template




Plan a healthy and well-balanced meal by synthesizing everything learned about digestion and nutrition.






Debate and defend unit essential questions by stating a claim and then supporting the claim with evidence from the entire unit.


4 days


  • “An Oasis on Wheels”





Design a way to get more nutritious foods to families and write a letter to your mayor to convince them to adopt your idea.



Common Core Standards

Language Standards
  • L.2.1 — Demonstrate command of the conventions of standard English grammar and usage when writing or speaking.

  • L.2.1.e — Use adjectives and adverbs, and choose between them depending on what is to be modified.

  • L.2.1.f — Produce, expand, and rearrange complete simple and compound sentences (e.g., The boy watched the movie; The little boy watched the movie; The action movie was watched by the little boy).

  • L.2.2 — Demonstrate command of the conventions of standard English capitalization, punctuation, and spelling when writing.

  • L.2.2.b — Use commas in greetings and closings of letters.

  • L.2.4 — Determine or clarify the meaning of unknown and multiple-meaning words and phrases based on grade 2 reading and content, choosing flexibly from an array of strategies.

  • L.2.6 — Use words and phrases acquired through conversations, reading and being read to, and responding to texts, including using adjectives and adverbs to describe (e.g., When other kids are happy that makes me happy).

Reading Standards for Informational Text
  • RI.2.1 — Ask and answer such questions as who, what, where, when, why, and how to demonstrate understanding of key details in a text.

  • RI.2.10 — By the end of year, read and comprehend informational texts, including history/social studies, science, and technical texts, in the grades 2—3 text complexity band proficiently, with scaffolding as needed at the high end of the range.

  • RI.2.2 — Identify the main topic of a multiparagraph text as well as the focus of specific paragraphs within the text.

  • RI.2.3 — Describe the connection between a series of historical events, scientific ideas or concepts, or steps in technical procedures in a text.

  • RI.2.4 — Determine the meaning of words and phrases in a text relevant to a grade 2 topic or subject area.

  • RI.2.5 — Know and use various text features (e.g., captions, bold print, subheadings, glossaries, indexes, electronic menus, icons) to locate key facts or information in a text efficiently.

  • RI.2.6 — Identify the main purpose of a text, including what the author wants to answer, explain, or describe.

  • RI.2.7 — Explain how specific images (e.g., a diagram showing how a machine works) contribute to and clarify a text.

Reading Standards: Foundational Skills
  • RF.2.4 — Read with sufficient accuracy and fluency to support comprehension.

Speaking and Listening Standards
  • SL.2.1 — Participate in collaborative conversations with diverse partners about grade 2 topics and texts with peers and adults in small and larger groups.

  • SL.2.2 — Recount or describe key ideas or details from a text read aloud or information presented orally or through other media.

  • SL.2.3 — Ask and answer questions about what a speaker says in order to clarify comprehension, gather additional information, or deepen understanding of a topic or issue.

  • SL.2.5 — Create audio recordings of stories or poems; add drawings or other visual displays to stories or recounts of experiences when appropriate to clarify ideas, thoughts, and feelings.

  • SL.2.6 — Produce complete sentences when appropriate to task and situation in order to provide requested detail or clarification.

Writing Standards
  • W.2.1 — Write opinion pieces in which they introduce the topic or book they are writing about, state an opinion, supply reasons that support the opinion, use linking words (e.g., because, and, also) to connect opinion and reasons, and provide a concluding statement or section.

  • W.2.2 — Write informative/explanatory texts in which they introduce a topic, use facts and definitions to develop points, and provide a concluding statement or section.

  • W.2.5 — With guidance and support from adults and peers, focus on a topic and strengthen writing as needed by revising and editing.

  • W.2.8 — Recall information from experiences or gather information from provided sources to answer a question.