1. With your host… Arnold Schwarzenegger
The Muscular System
With your host…
Arnold Schwarzenegger

2. ?
What do muscles do?
Muscles move you! Without muscles you couldn't open your mouth, speak, shake hands, walk, talk, or move your food through your digestive system. There would be no smiling, blinking, breathing.
Muscles turn energy into motion. (Think of all the things you do that you need your muscles for! It would be impossible for you to do anything without your muscles!)

3. That’s about the weight of THREE African Elephants!
Did you know…?
If all 600+ muscles in your body pulled in one direction, you could lift 25 tons!!!
That’s about the weight of THREE African Elephants!

4. Types of Muscles

5. Smooth muscles
Also called involuntary muscles (Your brain and body tell these muscles what to do without you even thinking about it.)
Located in your internal organs.
Examples: in diaphragm, walls of digestive organs.

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

7. Skeletal Muscle
Also called voluntary muscle. (They only work when you specifically tell them what to do).
These are the muscles that we can see, feel, and control.
Make up 50% of your body weight.
Examples: bicep, tricep.

8. What's the job of skeletal muscle?
Body movement
Posture
Body heat
Communication

9. Major Skeletal Muscles

10. How do you move? You move because pairs of muscles work together.
When one muscle of a pair contracts, the other relaxes.
Flexor - muscle that flexes, or bends a joint
Extensor - muscle that extends, or straightens a joint
Muscles always pull!

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12. Other muscle knowledge…
Over time, muscles can become larger or smaller, depending on whether or not they are used.
Blood carries energy-rich molecules to the muscles so they can do their work.

13. Let’s Review…