Skeletons & Muscles
Identify that humans and some other animals have skeletons and muscles for support, protection, and movement
What a learner can do afterwards
- Name the three functions of the skeleton: support, protection, movement
- Identify that muscles are attached to bones and pull to create movement
- Give examples of bones protecting organs (skull protects brain, ribs protect heart and lungs)
1 · Read
You can see fur, feathers, and scales outside. Inside, bones link to make your skeleton, and muscles wrap around bones. Together they hold you up, protect soft parts, and let you move.
Support means holding you up. Your skeleton works like the frame inside a tent. Without the frame, the tent would flop to the ground. Without your skeleton, your body could not stand or sit up straight.
When Maya trips and falls, her skull protects her brain from the bump. Her ribs curl around her chest like a cage, keeping her heart and lungs safe underneath.
Bend your arm and feel the front of it. That firm bump is a muscle pulling on the bone below your elbow. Muscles can only pull, never push, so they work in pairs to bend and straighten your arm.
Your skeleton and muscles work together: bones support and protect you, and muscles pull on bones to make you move.
The rewritten readings were written for this dataset.
More to read
Your body's bone frame
All your bones together form your skeleton. This frame holds your body upright and gives it shape. Without it, you could not keep your body up to sit or stand.
Bones also guard delicate organs. The skull surrounds your brain with a hard shell. Ribs wrap around the chest to protect the lungs and heart.
Muscles help this frame move. They pull on bones, moving the body parts joined to them. A muscle can pull but cannot push.
There are two main groups of bones. The central group includes your skull, backbone, ribs and breastbone. The other group includes your limbs and the shoulder and hip bones that attach them.
Bones have jobs inside them too. Soft marrow in some bones produces blood cells. Bones store minerals your body needs.
When you jump, run or play, muscles pull your supporting frame into motion while bones keep protecting your organs.
Bones that support, protect and move
Your bones join to form a sturdy frame inside you: your skeleton. It holds you upright, shields delicate organs and helps muscles move your body.
Around your brain sits the hard skull. Curved ribs protect the lungs and heart in your chest.
To bend an arm or kick a ball, some muscles shorten and pull on the bones they are attached to. Those pulls move parts of your body.
Dogs, birds and cats also carry bony skeletons inside their bodies. A crab has a hard outer skeleton instead.
Five jobs of bones and muscles
Bones, muscles and stretchy tissues help hold your body together. They have five main jobs.
Support: a bony frame holds you upright and gives you shape.
Movement: muscles pull rather than push. Pulling bones helps you walk or wave. Some muscles pull on skin to make a smile.
Protection: the skull guards your brain, while ribs shield the lungs and heart.
Storage: bones keep minerals until your body needs them, much as a pantry holds food.
Blood cells: soft marrow in some bones makes new ones each day.
Nerves help control movement. Messages from your brain tell muscles when to pull. Bones, muscles and nerves work together as you play or run.
2 · Watch
به انگلیسیTake it off screen
Where it sits
Learn first
Optional connections
This opens up
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.