1. Every time you move, Your muscles are doing work. Video
The Muscular System
Every time you move,
Your muscles are doing work.
Video

2. Extend and curl your arm. What muscles are working?
Contracting
When one muscle is contracting, the other is relaxing…

3. Three different types of muscles
Skeletal
Voluntary
Attached to bones
By thick strands of connective tissue
Tendons
Connect muscles to bone
Allows us to do lots of activities
Most muscles work in pairs

4. Smooth Muscles Not under voluntary control
These work automatically when your body needs them to
Found with organs that are used in digestion

5. Cardiac Muscle
Found only in the heart
Involuntary

6. Muscle Contraction Contracting Muscles get shorter and thicker
They contract because their cells can become shorter
Muscle cells/fibers contract when they get a nervous impulse from the brain

7. Even when muscles aren’t moving, some of their fibers are contracting
Muscle tone
Slight, constant contraction due to contractions of muscle fibers
This helps maintain our posture
Keeps our head up, not enough to turn our head, but enough to keep your head up

8. Energy and Muscle Contraction
Muscles use energy when they contract
This energy is from a chemical reaction in our muscle cells
Use sugar glucose that is made from the food you eat
Sugar glucose + Oxygen = energy

9. If you are really active, O2 can’t keep up with glucose, so a chemical reaction happens that doesn’t need O2.
This produces lactic acid
This causes your muscles to get tired

10. Reflexes Reflexes An automatic movement that happens quickly
Happen to muscles that we have voluntary control over

11. Activity
In groups, make up a test to test your reaction time (no one should get hurt!)
Be prepared to share in front of the class

12. Caring for your muscles
(write down 3 of these)
Get regular exercise
Eat high protein foods
Practice good posture to strengthen back muscles
Warm up and cool down to prevent injury
Lift correctly

13. Get out a yellow book and turn to Page 389
In your notes define: Bruises, muscle strains or sprains, tendinitis, hernia, and muscular dystrophy