1. JH-KEADLE
The Muscular System

2. Procedure
Flex your right arm and wrap your left hand around your bicep and triceps muscles.

3. Procedure
Bend and straighten your arm several times and feel the two main muscles working under your skin.

4. Procedure
Working in pairs, help each other to measure your bicep length while it is relaxed (straightened). Use centimeters.

5. Procedure
Working in pairs, help each other to measure your bicep length while it is contracted (flexed). Use centimeters.

6. Procedure
Working in pairs, help each other to measure your triceps length while it is relaxed (bent). Use centimeters.

7. Procedure
Working in pairs, help each other to measure your triceps length while it is contracted (straight). Use centimeters.

8. Procedure
Now measure the circumference of your upper arm while bent and straight. Use centimeters.

9. How did the biceps and triceps change as you bent and straightened your arm?
When the arm was extended, the biceps would relax (lengthen) and the triceps would contract (shorten). The reverse happen when the arm is bent.

11. Muscles are the motors that move body parts
Bones and joints cannot move on their own
There are approximately 600 muscles in your body
35 – 40% of body mass is muscle

12. Functions of the Muscular System
pumps blood through your body.
moves food through your digestive system
allows you to breathe.
allows you to move.

13. muscle
vocabulary
word!
muscle – the tissue that contracts and relaxes, making movement possible.

14. voluntary muscles voluntary muscles - muscles under conscious control
vocabulary
word!
voluntary muscles - muscles under conscious control
smiling, walking, running, typing etc…

15. involuntary muscles
vocabulary
word!
involuntary muscles - muscles not under conscious control
You don’t have to think about them
breathing, digesting, sneezing, heart beating

16. organs of the muscular system
smooth muscle
cardiac muscle
skeletal muscle
tendons

17. smooth muscle
smooth muscle – involuntary muscle found in internal organs and blood vessels and helps move things around the body.
blood vessels
digestive system

18. smooth muscle

19. cardiac muscle
cardiac muscle – involuntary muscle that makes up the heart. Cardiac muscle cells have a lot of mitochondria and do not tire.

20. cardiac muscle

21. skeletal muscle
skeletal muscle – voluntary muscle that is attached to bones and helps you move. Skeletal muscle can become tired. They work in pairs.

22. skeletal muscle

23. tendon
vocabulary
word!
tendon – tough strand of tissues that connects a muscle to a bone.

24. muscles at work
Skeletal muscle movements are results of pairs of muscles working together.
One muscle contracts while the other muscle relaxes.
Muscles always pull;
they never push.

25. muscles at work

26. muscles at work Results of Muscle Action Muscles contract
This produces thermal energy, and it uses chemical energy.
Thermal energy produces heat that helps keep body temperature constant.
Chemical energy is from glucose. (When glucose is used up, muscles are tired and need to rest.)