How are our bodies organised?
Every living thing is made of cells. Cells are tiny: you need a microscope to see them. Some living things have only one cell, and others, like you, have trillions: about 30 million million cells!
A living thing with only one cell. Example: a paramecium, which lives in ponds.
A living thing with many cells. Examples: a dog, a tree, you! Our body has many different kinds of cells.
From cells to systems
In a multicellular body, cells work in teams. Small teams join to make bigger teams. Read the steps from left to right:
Cells of the same type joined in layers. Example: muscle tissue in the heart.
Different tissues working together to do one job. The heart has muscle, connective and nerve tissue, and its job is to pump blood.
Several organs working together. The heart, arteries and veins make the circulatory system.
The whole living thing. All your systems together make you!
Scientists ask a lot of questions! Use What for things (What is a tissue?), Where for places (Where does digestion begin?), Why for reasons (Why do we sweat?), How for the way something happens (How does the heart work?), and Which to choose (Which organ has four parts?).
