This document discusses the three main types of muscles in the human body: skeletal, smooth, and cardiac muscles. Skeletal muscles are voluntary muscles that are attached to bones by tendons and allow for movement of the body. Smooth muscles are involuntary and control internal organs. Cardiac muscle is only found in the heart and contracts involuntarily around 70 times per minute each day. The document explains how muscles contract to create movement and require energy from glucose to function properly.

1. The Muscular System
Chapter 4
Lesson 2

2. Science Words
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Muscle
Voluntary muscle
Involuntary muscle
Skeletal muscle
Tendon
Smooth muscle
Cardiac muscle

3. Moving the human body
Muscle-an organ that
contracts and gets
shorter- this provides
the force to move
your body parts.
Muscles of the
body

4. Muscle Control
• Voluntary musclesmuscles that you are
able to control.
• Examples are leg and
arm muscles
• Involuntary Musclesyou can not move them
consciously. They just
keep working.
• Example- heart

5. Types of Muscles
*Smooth
*Cardiac
*Skeletal

6. Smooth Muscles
• Smooth muscles are
non-striated
• Involuntary movement
• Move the internal organs
• Contract and relax slowly.
• Example- small intestine

7. Cardiac Muscle
• Cardiac muscle are
found only in the heart.
• Involuntary movement.
• Striations
• Contracts about 70 times
a minute every day of
your life.

8. Skeletal Muscles
• Skeletal Muscles-muscles
that move bones.
• Attached to the bones by
tendons.
• Most numerous in the body.
• Look striped or striated.
• Voluntary muscles.

9. How Muscles Work
• Skeletal muscles-when one
muscles contracts- another
muscle relaxes.
• Muscles always pull- never
pushes.
• Muscles use glucose (sugar)
• Produce energy when they
contract.
• Muscles that are not
exercised become smaller.

10. Muscles and bones work together