How Organ Systems Work Together

About this printable How Organ Systems Work Together science reading passage, NGSS-aligned (Grades 3-5)

This engaging 250-word reading passage introduces fourth-grade students to the concept of how organ systems work together in the human body. Aligned with NGSS standard 4-LS1-1 and the Disciplinary Core Idea LS1.A, the passage explains that body systems do not work independently. Students discover how the lungs bring in oxygen while blood carries it throughout the body, how the stomach breaks down food while blood delivers nutrients to cells, and how multiple systems coordinate during activities like running. The passage uses simple, age-appropriate language and real-world examples to build foundational understanding. Audio integration supports diverse learners by providing multiple ways to access the content. The passage includes bolded key vocabulary terms with immediate definitions, helping students build science literacy. Students explore the interconnected nature of the respiratory, circulatory, digestive, and muscular systems through concrete examples they can relate to their own experiences. This resource prepares students for hands-on investigations and classroom discussions about human body systems and their functions.

Written by Workybooks TeamPublished by Workybooks

Sample passage and quiz from How Organ Systems Work Together

Your body has many different organ systems—groups of organs that work together to do important jobs. These systems do not work alone. They depend on each other to keep you healthy and alive.

The lungs are organs that bring oxygen from the air into your body. Oxygen is a gas that all your cells need to stay alive. But the lungs cannot deliver oxygen by themselves. The blood—a liquid that flows through your body—carries the oxygen from the lungs to every cell. Think of blood as a delivery truck that picks up oxygen at the lungs and drops it off wherever it is needed.

The stomach is an organ that breaks down food into tiny pieces called nutrients. Nutrients are substances your cells need for energy and growth. Once again, the blood carries these nutrients from the stomach to all the cells in your body.

When you run or play, your muscles work hard and need more oxygen and nutrients. Your heart beats faster to pump blood more quickly. You also breathe harder so your lungs can bring in more oxygen. Three systems—respiratory, circulatory, and muscular—are working together.

If one system stops working, the others are affected too. Without lungs bringing in oxygen, the blood has nothing to deliver. Without blood, nutrients from the stomach cannot reach your cells. Body systems are like teammates—they all need each other to win the game.

Interesting Fact: Your heart beats about 100,000 times every single day, pumping blood to deliver oxygen and nutrients throughout your entire body!