1. The Muscular System

2. CAN YOU SIT STILL AND NOT MOVE A MUSCLE?

3. CAN YOU SIT STILL AND NOT MOVE A MUSCLE?
Are you breathing?
Is your chest expanding?
Are you producing saliva(spit) in your mouth?
Did you swallow?

4. IT IS IMPOSSIBLE TO SIT STILL AND NOT MOVE A MUSCLE!!
Approximately 40% of your body weight is made up of muscles.

5. HOW MANY MUSCLES DOES A BODY HAVE?
Almost 700 countable skeletal muscles
Several million hair-raising muscles
Several billion smooth muscles cells blended together
Exactly 1 heart muscle

6. Types of Muscles 2 groups of muscles in the body
Involuntary – you have no control over
Ex’s: Breathing and Digesting Food
Voluntary – you have control over
Ex’s: Smiling, Getting out of your chair

7. 3 TYPES OF MUSCLES

8. TYPES OF MUSCLES Skeletal
Location – attached to the bones of your skeleton
Voluntary
Striated (banded)

9. SKELETAL MUSCLES Move and support the skeleton
Skeletal muscles react quickly and tire easily
There are over 600 skeletal muscles

10. TENDON
A strong connective tissue that attaches skeletal muscles to bones

11. TYPES OF MUSCLES Smooth Location – Inside many internal organs
Involuntary
Not striated

12. SMOOTH MUSLCES
Found on the inside of the stomach, blood vessels, and intestines.
React slowly and tire slowly.

13. TYPES OF MUSCLES
Cardiac
Location – Heart only
Involuntary
Striated

14. CARDIAC MUSLCES Involuntary Muscle Muscle cells are striated
Does NOT get tired
It contracts repeatedly this is called a heartbeat

15. MUSCLES AT WORK Muscles work by CONTRACTING.
What does a contracting muscle look like?
Muscles become shorter and thicker.
When do muscles contract?
When they receive messages from the nervous system

16. MUSCLES PULL NOT PUSH!
Skeletal muscles can only contract and must work in pairs
While one muscle contracts, the other muscle relaxes and returns to its original length.

17. HOW DO MUSCLES WORK? To bend the elbow
The bicep muscle contracts (gets shorter)
The triceps muscle contracts to return bicep to its original length