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Our Lungs Our Air Our Health

Activity 3 (Explain): The Respiratory &

Circulatory Systems

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Activity Overview

Activity Summary

In this activity, students use an online simulation to build background knowledge of how the respiratory and circulatory systems interact. They then use this information to compare and contrast the two systems using a Venn diagram.

Activity Objectives & Materials

Approximate Time: 45 minutes


  • Students will know the main parts of the human respiratory system and what they are for

  • Students will know the main parts of the human circulatory system and what they are for

  • Students will know critical facts about the human respiratory system, ex. that oxygen is the gas in the air we need, and carbon dioxide is the gas we need to get rid of



  • Computer & Projector

  • Student computers (recommended)

  • Headphones for students (for video) or speakers

  • Red & blue (or purple) colored pencils or markers (optional)

  • Vacuum cleaner hose (optional)



  • Respiratory and Circulatory Systems (diagram and graphic organizer) w/ teacher guide

Standards Connection

DCI: LS 1.A: Structure & Function

CCC: Systems & System Models



Why do we need to breathe?

  • This seemingly simply question can have answers that range from the basic (“to get air”) to the complex (“to bring in oxygen that our cells need to get energy from food and remove carbon dioxide that our cells need to get rid of). The goal of this warmup is to activate students’ background knowledge and get a survey of what they already know before the activity.


1. Frame the Activity

Tell students that understanding what is happening to Tatiana and Calvin means we need to understand what’s happening when air goes into their bodies. In this activity, they will build that understanding by learning more about human body systems.

2. Charting Background Knowledge

Use the warmup to hold a short discussion with students about what they already know about the respiratory system. Add these details to the class KWL chart they made in Activity 1 (and their individual charts if they have them). Students may already know things like “lungs are in the respiratory system” and “you breath oxygen and breathe out carbon dioxide.” Limit the chart to what students already know. Be sure to use questions to determine students’ understanding of the idea that the respiratory system is made of individual organs such as the lungs and trachea, and why it is called a “system” (because it is made of parts (organs) that work together).

3. Organs of the Respiratory System

Hand out the Respiratory and Circulatory Systems sheet to students. Display the diagram of the respiratory system (below) where all students can see it, and go over the organs. If students already know some organs, start with the ones they know. Have students label their own diagrams as you go. NOTE: Some parts of the system have been left labeled because they are less critical for students to memorize. Use the organ/organ system language when describing the parts to help students internalize the “organs make up an organ system” concept.

Key vocabulary:

Organs of the Respiratory System.jpg

Differentiation: Provide pre-filled copies of the respiratory system diagram to students (but still discuss the parts with them)

Teacher Tip: Students should be able to use appropriate scientific terminology when talking about the respiratory system, but don’t get bogged down in having students memorize a list of individual organs. This module focuses on the big concepts of human health and air pollution and should not feel like an anatomy lesson.

Teacher Tip: A vacuum cleaner hose is a great way to show students what the trachea is like. It is flexible and rigid at the same time to allow air to flow even when you move your body around, yet it doesn’t collapse when pressed on because of rings of cartilage that give it structure.

Step 4

4. Lung Attack Simulation

Have students take out their KWL charts from Activity 1, and tell them that they are going to use a simulation to learn more about how humans breathe. As they watch the simulation, they should add things they learned to the “Learned” section of their KWL chart (if they run out of room they can start on the back or get another KWL chart). Pass out student computers (if available) and have them complete the “Normal Breathing” section of the Lung Attack simulation. If student computers are not available, you can run the simulation together using a projector.​


After students have completed the simulation, have them turn to a partner to compare what they learned and add anything they are missing to their charts. Then have the whole class share out what they learned, and add this information to the class KWL chart. One critical point to highlight is the fact that the respiratory system is the only way for humans to get oxygen into our bodies that our cells need to function.

Key takeaways:

  • Oxygen is the gas in the air our body needs

  • Our whole bodies need oxygen

  • We get oxygen into our bodies through our lungs

  • Alveoli are the part of our lungs where oxygen gets into our blood and carbon dioxide comes out

  • Hemoglobin carries oxygen around our bodies

5. How the Circulatory System Works

Ask students what happens to oxygen once it gets into our blood. They should remember from Lung Attack that it gets delivered throughout our bodies. Direct students’ attention to the circulatory system diagram on the right side of their handouts. Tell students that to understand more about how this works, they’re going to watch a video called “Exploring the Heart.” Have students go to the video here (or show it using the projector): , and have them follow along on their diagrams as they trace the path of a red blood cell.

After the video, have students add arrows to their diagrams showing the flow of blood through the circulatory system. If colored pencils or markers are available, have students color in the key to the diagram (red is oxygen-rich/CO  -poor blood, blue or purple is oxygen-poor, CO  -rich blood) and color in the blood vessels in their diagram. You may want to do this together or display a color version of the diagram to help students draw the arrows and color the diagram correctly. Also be sure to ask students what the primary organ of the circulatory system is (the heart) to reinforce the organ/organ system idea.



Teacher Tip: This part of the activity is a good place to reinforce students’ understanding of cells, and where they fit into the hierarchy of cells-tissues-organs-organ systems. If students are new to cells, it is worth taking a brief moment to define what a cells is and what other cells they’ve heard of ex: skin cells.

Circulatory System.jpg

Connection to Activity 2: Ask students what they were feeling when they were measuring heart rate in Activity 2 (the pressure from heart beats on their chest or through their blood vessels)

Organs of the circulatory system?: Blood vessels such as arteries, veins, and capillaries are sometimes considered organs of the circulatory system, mainly because like other organs they are made of different kinds of tissues and serve a distinct function. However, since they are so different from other human organs, they are frequently not identified specifically this way. If students ask, you can ask them what they think, and then provide this information to support their understanding.

6. Formative Assessment

Have students complete the Venn diagram showing similarities and differences between the respiratory system and the circulatory system. You may want to give them a few hints to get them started. Check to see if students have the key points identified in the teacher guide. The “other important information” section can include other facts they’ve learned.

Differentiation: Have students complete the Venn diagram with a partner instead of on their own.

Suggested responses:

Respiratory Circulatory Systems Venn Dia
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