Grown-up notes

Each line is marked Fact well established, Model a deliberate simplification, or Unsure not settled.

Play another way

Another connection: Where does food come from?

The idea

• FactThe heart is a muscle that pumps blood around the body. It is about the size of your own closed fist and sits behind the breastbone, a little to the left.
• FactWhen you run, your muscles need more of what blood carries, so the heart beats faster and you breathe faster. When you rest, both slow down again.
• ModelThe toy uses 90 beats a minute at rest and 150 while running so the change is easy to notice. These are illustrative settings, not a target or a way to judge a child's health. Heart rate varies with age, activity and other factors.
• FactThe lungs sit either side of the heart. The left lung is a little smaller, leaving room for the heart.
• FactBones give the body its shape and hold it up. An adult has about 206. A baby is born with closer to 300 pieces, many of them still soft cartilage, and they join together as the child grows.
• FactThe brain sends messages to the body along nerves, and the body sends messages back.
• FactBlood is always red. It is a brighter red on the way out from the heart and lungs and a darker red on the way back. Veins only look blue through skin.

What the pictures simplify

• Model"The brain is the boss." True for moving on purpose, as in the brain scene. But the heart starts each beat by itself, using its own built-in pacemaker; the brain only speeds it up or slows it down. And some quick reactions, such as the knee jerk, are handled by the spinal cord without waiting for the brain.
• ModelMessage speed. Real nerve messages travel at up to about 100 metres a second. The sparks are slowed enormously so she can watch them.
• ModelNerves and blood vessels. The yellow and red lines stand for thousands of fine branches that reach every part of the body.
• ModelFewer bones. The skeleton is drawn with one bone in each forearm and lower leg, where there are really two, and with simple hands, feet, ribs and backbone.
• ModelFewer organs. Only the brain, lungs, heart, stomach and intestines are drawn. The liver, kidneys and others are left out, and muscles are not shown as a layer.
• ModelThe heart's shape. It is drawn as a rounded lump with two tubes. A real heart has four chambers inside.
• ModelThe floppy puddle. Without bones you could not stand, but muscles and skin would still hold some shape. The puddle is exaggerated for fun.
• ModelPulse. The caption calls the heart's beat your pulse. Strictly, the pulse is the push of blood you can feel in an artery, at the wrist or neck, each time the heart beats.

Questions she may ask

• Does my heart ever stop for a rest? FactNo. It beats all day and all night, even while you sleep. It rests for a tiny moment between each beat.
• Why is blood red? FactRed blood cells contain haemoglobin, which carries oxygen from the lungs to the body. Oxygen is one part of the air we breathe; whole bubbles of air do not travel round in our blood.
• Do bones grow? FactYes. Bones are alive. They grow as you grow, and if one breaks it can mend itself.
• What is the tummy rumble? FactYour stomach and intestines squeezing food, liquid and air along.
• Can I see inside a real person? FactDoctors can, with an X-ray, which makes a picture of your bones, or with other scanners that show the soft parts.
• Is everyone the same inside? FactPeople share a basic body plan, but bodies vary. Some people are born with differences or have changes from illness, injury or surgery. Bodies can work in different ways.

Words this guide teaches

Skeleton: all your bones together. Lungs: the two soft bags in your chest that breathe air in and out. Pulse: the beat you can feel when your heart pumps.

Go further

See Inside Your Body by Katie Daynes, illustrated by Colin King (Usborne). A lift-the-flap book with more than a hundred flaps, which suits the same "lift a layer away" idea. Australian booksellers list it and a newer 2024 board-book edition; try your library first.

Sources

• healthdirect, "Resting heart rate": feeling a pulse at the wrist and the factors that change heart rate.
• healthdirect (Australian Government), "Heart": size, position and job of the heart.
• The Royal Children's Hospital Melbourne, "Acceptable ranges for physiological variables": hospital observations for unwell children; not a healthy resting range for this activity.
• Live Science, "If blood is red, why do veins look bluish?": blood is never blue.
• Frontiers in Physiology (2020), review of the sinoatrial node: the heart starts its own beat.

Checked November 2026. The bone counts, nerve speed, the smaller left lung and the answers to her questions are standard anatomy and physiology, confirmed by search results or recalled, not each taken from a linked page.