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Muscles

By:

Ms Bintang Simaremare

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Learning Objectives

Explore the role of the skeleton and joints and the principle of antagonistic muscles.�

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Muscles

  • Muscles are organs that help us to move.
  • The muscles are attached to the bones by tendons. Tendons are very strong and the do not stretch.

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Main muscles in the upper arm

  • There are two main muscles in the upper arm:
    • Biceps muscle
    • The biceps has two tendons attaching its upper end to bones.
    • Triceps muscle
    • The triceps has three tendons attaching its upper end to bones.

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How muscles work

  • Muscles can pull, but they cannot push
  • Muscles work by getting shorter. We say that they contract, and the process is called contraction.
  • When a muscle contracts, it pulls on the radius and scapula, and the bone can move if it is part of a joint.

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Antagonistic muscles

  • These are the biceps on the front of the upper arm and the triceps on the back of the upper arm:
    • to raise the forearm, the biceps contracts and the triceps relaxes.
    • to lower the forearm again, the triceps contracts and the biceps relaxes
  • A pair of muscles that work together, pulling in opposite directions are called antagonistic muscles.

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  • THANK YOU