The Muscular System

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The Muscular System

• Life Science

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What is a muscle?

• A muscle is an organ that can relax and contract,
  and provides the force to move your body parts.

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Voluntary muscles

• Muscles that you are able to control

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Involuntary muscles

• Muscles that you cannot control.

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Three types of muscle tissue

• Skeletal muscle
• Smooth muscle
• Cardiac muscle

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Skeletal Muscle

• Used to move bones
• Most common type of muscle
• TENDONS are thick bands of tissue that attach
  muscle to bones.

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More on skeletal muscle

• Skeletal muscles are voluntary muscles.
• They contract quickly and tire more easily.
• They look striped or striated.

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Smooth Muscles

• Are found in internal organs
• For example, the intestines
• Smooth muscles are involuntary muscles
• They contract and relax slowly.

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Cardiac Muscle

• Found only in the heart.
• Cardiac muscle is striated, like skeletal muscle.

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How do muscles work?

• You move because pairs of muscles work together.
• When one muscle contracts, the other relaxes.
• Muscles always pull.
• Over time, muscles can become larger or smaller,
  depending on there or not they are used.
• Blood carries energy-rich molecules to the
  muscles so they can do their work.