Page 10 - E-Science Prim.6 2024-2025 U1 Con.2,3_Handy

The arm moves due to contraction and relaxation of muscles
connected to the arm bones by this way:

1- Forearm moves up when the in front muscle contracts and
the back muscle relaxes.

2- Forearm moves down when the in front muscle relaxes and
the back muscle contracts.

Characteristics of muscles

Skeletal muscles are attached to the bones of skeletal system.
They contract and relax to allow bones to move.

Muscle can exert effort when it contracts “shorten in length”
(Muscles work by contraction)

Contraction of muscles moves the bones in 1 direction only.
Skeletal muscles are often work in pairs in opposite directions.

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First Term