How Muscles Move Bones

Science · The Human Body · ages 7-9

Name ______________________ Date ____________

Which word means a muscle that you choose to use, like the ones in your legs when you kick a ball?
- Voluntary
- Involuntary
- Automatic
When you bend your arm, what happens to your bicep muscle?
- It relaxes and gets longer
- It contracts and pulls
- It stops working
The heart is a voluntary muscle that you can choose to stop.
Circle one: True False
Maya's stomach muscles squeeze her food along after lunch, and she never has to think about it. What kind of muscle is this?
- Voluntary
- Involuntary
- It is not a muscle
When you straighten your arm, what does your triceps do?
- It relaxes while the bicep does the work
- It stays the same, doing nothing
- It contracts and pulls
Voluntary muscles work automatically without you thinking about them.
Circle one: True False
A patient is asleep and not thinking about their heart at all, yet a doctor's stethoscope picks up a steady heartbeat. Why does this happen?
- The heart is a voluntary muscle that works even during sleep
- The heart stops when you are not thinking about it
- The heart is an involuntary muscle, so it works automatically
Jay bent his arm and said, 'Both my bicep and triceps are pulling hard at the same time.' What is wrong with what Jay said?
- One muscle pulls while the other relaxes, they do not both pull at once
- Nothing is wrong, muscles always pull together
- Only the triceps ever pulls

Answer key

For grown-ups. Fold this page away before handing over the rest.

Voluntary · Voluntary muscles move when you decide to move them.
It contracts and pulls · The bicep contracts, which means it gets shorter and pulls your arm to bend.
False · The heart is involuntary. It beats on its own, all day and night, without you telling it to.
Involuntary · Digestive muscles work automatically, without Maya choosing to move them, so they are involuntary.
It contracts and pulls · To straighten your arm, the triceps contracts and pulls, while the bicep relaxes.
False · That describes involuntary muscles. Voluntary muscles move only when you choose to use them, like when you wave your hand.
The heart is an involuntary muscle, so it works automatically · The heart is involuntary. It keeps working on its own, even while you sleep or are not thinking about it.
One muscle pulls while the other relaxes, they do not both pull at once · Muscles work in pairs. When the bicep pulls to bend the arm, the triceps relaxes, so they take turns, not pull together.