---
title: "Cells, Tissues & Organs"
description: "Understand that the body is organised in a hierarchy: tiny cells are the building blocks, groups of similar cells form tissues, tissues combine into organs (like the heart or stomach), and organs work"
canonical: https://lightmysky.com/learn/science/cells-tissues-and-organs-mt_C7FNeIDGc6
source: https://lightmysky.com/learn/science/cells-tissues-and-organs-mt_C7FNeIDGc6.md
retrieved: 2026-11-12
---

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# Cells, Tissues & Organs

Understand that the body is organised in a hierarchy: tiny cells are the building blocks, groups of similar cells form tissues, tissues combine into organs (like the heart or stomach), and organs work together in organ systems (like the circulatory system)

Subject: Science · Area: The Human Body · Ages 7 to 9
Page: https://lightmysky.com/learn/science/cells-tissues-and-organs-mt_C7FNeIDGc6

## Ready when they can

- State that cells are the body's smallest living units and that most individual body cells need a microscope to be seen clearly
- Describe the hierarchy: cells → tissues → organs → organ systems
- Give an example: muscle cells form muscle tissue; muscle tissue and other tissues form the heart; the heart works with blood vessels in the circulatory system

## Lesson: Cells, Tissues, and Organs: How Your Body Is Built

Your body contains trillions of cells. A cell is the body's smallest living unit. Most individual body cells are too small to see clearly with your eyes alone. A microscope makes them look larger so you can study them.

*(drawing: Follow the building order: cells form tissues, tissues form organs, and organs work in organ systems.)*

When many similar cells work together, they form a tissue. Different tissues work together in an organ, such as your heart, brain, lungs or stomach. Organs work together in an organ system. To place a part in this building order, check what it is made of and what it works with. Measuring its length does not tell you its level.

**Example.** Muscle cells work together in muscle tissue. In your heart, muscle tissue works with other tissues. Together, these tissues form the heart, an organ that pumps blood. The heart works with blood vessels in the circulatory system.

An organ system is not one large organ. The heart is one organ. It works with blood vessels in the circulatory system. This system moves blood around the body.

**Recap.** Cells are tiny building blocks that group into tissues. Tissues build organs, and organs team up to form organ systems.

*Original lesson, quiz and flashcard text written for this learning dataset.*

## Practice

8 questions on this page, each with its working shown.

## Optional connections

- [The Heart & Blood](https://lightmysky.com/learn/science/the-heart-and-blood-mt_lp1eTsQen7)
- [The Brain Controls the Body](https://lightmysky.com/learn/science/the-brain-controls-the-body-mt_pJ5zsocdNx)
- [How Breathing Works](https://lightmysky.com/learn/science/how-breathing-works-mt_tiPyEkm4cU)

## Opens up

- [The Immune System](https://lightmysky.com/learn/science/the-immune-system-mt_4JpMXUIxeD)
- [Structures for Survival](https://lightmysky.com/learn/science/structures-for-survival-mt_8VA40Tumth)
- [Tissue Types and How a Body Is Organised](https://lightmysky.com/learn/science/tissue-types-and-how-a-body-is-organised-mt_dQ-glI4kdz)
- [Heart & Blood Circulation](https://lightmysky.com/learn/science/heart-and-blood-circulation-mt_g_M4Vh_pK7)
- [Organ Systems Vocabulary](https://lightmysky.com/learn/science/organ-systems-vocabulary-mt_K8DJzqbksM)