1. Muscular System

2. What does the muscular system do?
Allows us to move our bodies
Keeps our bodies warm
Protects our joints
What does the muscular system do?

3. What are muscles made of?
Muscles are made of muscle fibers.
Muscle fibers are made up of long, paired strands of proteins.
What are muscles made of?

4. Muscular System There are two groups of muscles:
Voluntary-Muscles we can control that are connected to bones and allow us to move.
Involuntary-Muscles we cannot control like the muscles that make our heart beat.
Muscular System

5. Three types of muscles:
Skeletal-voluntary muscle that attaches to bones
Smooth-involuntary muscle that are found inside the organs
Cardiac-involuntary muscle that the heart is made of.
Types of muscles

6. Even when your muscle is not contracting enough to cause movement, a few of its individual fibers are still contracting.
This doesn’t cause movement but it does tense and firm the muscle.
This slight tension is called muscle tone.
Example: your neck contracts just enough to keep your head up even when you are not moving your head.
Muscle tone keeps your muscles healthy and ready for action.
Muscle Tone

7. Muscles that cannot contract due to injury, or muscles that are not used often, will weaken and shrink
This is a condition known as atrophy
Atrophy

8. Muscles working together
Skeletal muscles work together to move the body. (contraction vs. extension)
The brain sends a signal to the muscles to either contract or relax.
Example: The biceps contract as the triceps extend to bend the arm.
Muscles working together

9. What causes muscles to get bigger when you exercise?
When you lift something heavy, the muscle fibers contract.
Repeated strong contractions cause the muscle fibers and the muscle itself to grow in diameter and strength.
Moderate contractions won’t increase the diameter much but it will increase the endurance by allowing it to obtain more oxygen.
What causes muscles to get bigger when you exercise?

10. Muscles need oxygen in order to produce energy for contraction
When muscles work really hard they use up all the oxygen at hand and less energy is available for contractions.
In order for muscles to keep working without oxygen there is a process that makes the chemical, lactic acid which provides small amounts of energy.
Lactic acid is poisonous to cells though. So the body needs time and rest to get more oxygen and erase the oxygen debt.
Muscles get tired…

11. Keeping your muscles healthy
Work your muscles!
Avoid muscle injuries – regular strengthening and stretching exercises can help prevent injuries.
Vary your exercise routine so that your are not always using the same muscles
Warm up before vigorous exercise and include a cool down
Stop exercising if you feel sharp or sudden pain
Prevent muscle cramps – stretch and drink plenty of water
Keeping your muscles healthy

12. A few main muscles…

13. More Muscle Info… https://www.youtube.com/watch?v=rMcg9YzNSEs
More Muscle Info…