Transcript Teen Health Course 3

Chapter 16
Your Body Systems
Lesson 2
Your Muscular System
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 muscular
system
The group of structures that give your body parts
the power to move
 skeletal
muscles
The muscles attached to bones that enable you
to move
 smooth
muscles
The muscles found in organs, blood vessels and
glands
 cardiac
muscles
Muscles found only in the walls of your heart
In this lesson, you will learn to
 explain the functions of the muscular system.
 identify how muscle types differ.
 describe ways to keep your muscular system healthy.
Comparing and Contrasting
Explain similarities and differences among the different
muscle types in the lesson.
Your Muscles
Your muscular system contains many muscles that
perform different functions.
muscular system The group of structures that give
your body parts the power to move
Types of Muscles
Skeletal muscles are the largest part of the body’s
muscular system.
skeletal muscles The muscles attached to bones that
enable you to move
Skeletal muscles are voluntary.
Types of Muscles
The mouth, stomach, and lungs are all composed
of smooth muscles.
smooth muscles Muscles found in organs, blood
vessels and glands
Smooth muscles are involuntary.
Types of Muscles
Cardiac muscles work continuously, even when you
sleep.
cardiac muscles Muscles found only in the walls of
your heart
Cardiac muscles are involuntary.
How Muscles Work
There are two basic and opposite actions that
account for all muscle movement.
Contraction
Extension
The shortening of muscle fibers.
The lengthening of muscle fibers.
Muscle movement is triggered by impulses.
How Muscles Work
1
When you bend your arm,
your biceps contract and pull
on a bones of your lower
arm. At the same time, the
triceps extend.
2
When you straighten your
arm, your triceps contract
and pull on the other bone in
your lower arm. At the same
time, the biceps extend.
Problems of the Muscular System
Muscle strain is caused by small tears in a muscle
or tendon.
Strains usually occur in large muscles that have
been overworked.
Problems of the Muscular System
Muscular dystrophy is an inherited disease, and
causes skeletal muscle tissue to gradually
waste away.
Care of the Muscular System
“Use it or lose it.”
• Regular exercise helps maintain the natural tension in
muscle fibers, called muscle tone.
• Regular exercise also keeps the cardiac muscles healthy.
• Eat well.
• Warm up before exercising or playing sports.
• Cool down after exercising or playing sports.
• Use exercise or sports equipment properly.
• Lift heavy objects properly.
Lesson 2 Review
What I Learned
Vocabulary What are skeletal muscles? Name five of
the major skeletal muscles in your body.
Lesson 2 Review
What I Learned
Describe What are the functions of the muscular
system?
Lesson 2 Review
What I Learned
List Give two suggestions for keeping the muscular
system healthy.
Lesson 2 Review
Thinking Critically
Apply A teen is doing bench presses in the school’s
weight room. During each repetition, he groans loudly.
When you ask if he is in pain, he replies, “Yes—but it’s
good pain.” How might you respond?
Lesson 2 Review
Thinking Critically
Evaluate A teen has been asked to carry some boxes
of books to a classroom. He stoops over and pulls a
box upward toward his chest. Should he continue lifting
this way?
End of
Chapter 16
Your Body Systems
Lesson 2
Your Muscular System
Click for:
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>> Chapter 16 Assessment