Muscles
Muscles move the body. A muscle can only pull: it gets shorter and fatter and pulls on the bone it is joined to. So muscles work in pairs, one bending a joint and the other straightening it again. Some muscles move when we decide, like those of the arms and legs; others work by themselves, like the heart and the stomach.
Depth 1 · Foundation
You know a muscle moves a bone by getting shorter and pulling, that muscles work in pairs, and which muscles move only when we decide.
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- 1
Foundation
You know a muscle moves a bone by getting shorter and pulling, that muscles work in pairs, and which muscles move only when we decide.