1. The Muscular System

2. The muscular system is made up of…
Muscles
and
Tendons

3. Functions of Muscles Hold your organs in place
Hold your bones together so that you can move
Help you chew your food
Open and close your eyelids
Pump your blood
Allow you to run and play
Help you to smile

4. Muscle Action Involuntary muscles •impossible to control completely
•not under your conscious control
•responsible for activities such as:
-breathing
-digesting food
Voluntary muscles
•muscles that are under your control
•actions controlled by voluntary muscles:
-smiling
-turning a page in a book
-getting out of your chair when the bell rings

5. Types of Muscles
Cardiac muscle
Skeletal muscle
Smooth muscle

6. Skeletal Muscle Functions
Attached to the bones of your skeleton
Provide the force that moves your bones
At each end of a skeletal muscle is a tendon
Tendon: a strong connective tissue that attaches muscle to bone
Skeletal muscle cells appear banded, or striated—sometimes called striated muscle

7. Skeletal Muscle Characteristics
Classified as voluntary muscles
React very quickly
- example: swimmer at a swim meet, leg muscles quickly push the swimmer off the block into the pool
• Skeletal muscles tire quickly
-example: by the end of the swim race, the swimmer’s muscles are tired and need a rest

8. Smooth Muscle Functions
Involuntary muscles
Found in the inside of many internal organs (walls of stomach and blood vessels)
Work automatically to control many types of movements inside your body (digestion)
Example:
-as the smooth muscles of your stomach contract, they produce a churning action, the churning mixes the food with chemicals produced by your stomach. This action and these chemicals help to digest the food

9. Smooth Muscle Characteristics
Smooth muscle cells are not striated
Behave differently than skeletal muscles
React more slowly and tire more slowly

10. Cardiac Muscle
Function -has characteristics in common with both smooth and skeletal muscles -involuntary
Characteristics -muscle cells are striated -cardiac muscle does not get tired -can contract repeatedly (repeated contractions heartbeats) -found only in the heart

11. Muscles at Work
Muscles do their work by contracting, or becoming shorter and thicker
Contract when they receive messages from the nervous system
Because muscle cells can only contract, not extend, skeletal muscles must work in pairs. While one muscle contracts, the other muscle in the pair returns to its original length.

12. Taking Care of Your Skeletal Muscles
Exercise- maintain muscular strength and flexibility
Makes individual muscle cells grow wider—causes whole muscle to become thicker
The thicker a muscle is, the stronger the muscle is
Flexibility- helps prepare your muscles for the work involved in exercising or playing
Use precautions to help prevent muscle injuries
Warming up
Using proper safety equipment

13. Injured Muscles
Muscle strain/pulled muscle– can occur when muscles are overworked or overstretched
Tendons- may be overstretched or partially torn
Too much exercise can lead to a skeletal muscle cramp
When muscles cramp, the entire muscle contracts strongly and stays contracted
Always follow medical instructions and rest your injured muscle or tendon until it heals

14. Fun Facts
You have over 30 facial muscles which create looks like surprise, happiness, sadness, and frowning.
Eye muscles are the busiest muscles in the body. Scientists estimate they may move more than 100,000 times a day!
The largest muscle in the body is the gluteus maximus muscle in the buttocks.
There are about 60 muscles in the face. Smiling is easier than frowning. It takes 20 muscles to smile and over 40 to frown.