Section 11.2 Your Muscular System
Myth No pain, no gain.
Fact Pain is not a sign of a good workout. Rather, pain
is a signal from your body that you are working too hard
or you have an injury. Continuing to exercise through
the pain could lead to a more serious injury.
Where do you think most teens get their information
about muscles? How factual do you think their
information is?
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Section 11.2 Your Muscular System
Your Muscular System
Goals/Objectives
Describe the functions of the three types of
muscles.
Explain how you can keep your muscular
system healthy.
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Section 11.2 Your Muscular System
Key Terms
Muscular System
The body system that consists of muscles that
provide motion and maintain posture.
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Section 11.2 Your Muscular System
The Muscles in Your Body
• Muscles move your eyes as you read.
• Muscles in your chest allow you to breathe.
• Muscles in your heart pump your blood.
• Every time your body moves, muscles are at work.
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Section 11.2 Your Muscular System
Types of Muscle
Your body has three types of muscle tissue that
perform different functions.
• Smooth muscle - is involuntary muscle that found
in many internal organs. causes movements
within your body.
• Cardiac muscle - is involuntary muscle that is
found only in the heart.
• Skeletal muscles – is voluntary muscle tissue that
is attached to bones you control to do activities,
such as walk or play a musical instrument.
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Section 11.2 Your Muscular System
Voluntary vs Involuntary Muscles
• Voluntary muscle is a muscle that a person can
control.
• Involuntary muscle is a muscle that functions without
a person’s control.
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Section 11.2 Your Muscular System
How Muscles Work
• All muscles do work by contracting, or becoming
shorter and thicker.
• Many skeletal muscles work in pairs.
• One muscle in the pair contracts to move the
bone in one direction.
• Then, the other muscle in the pair contracts to
move the bone back.
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Section 11.2 Your Muscular System
Muscle Pairs
Biceps contracted
Triceps relaxed
Biceps relaxed
Triceps contracted
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Section 11.2 Your Muscular System
Tendons
• A thick strand of tissue called a tendon attaches a
muscle to a bone.
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Section 11.2 Your Muscular System
Muscle Tone
• Even when a skeletal muscle is not contracting to
cause movement, a few of its individual muscle
fibers are still contracting.
• Contractions tense and firm the muscle.
• This slight tension is called muscle tone.
• Muscles that cannot contract due to injury, or are not
used often, will weaken and shrink, a condition
known as atrophy.
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Section 11.2 Your Muscular System
1
The Muscular System
1) Frontalis
2
8
3
4
5
8) Biceps
9
2) Temporalis
3) Trapezius
10
9) Triceps
11
10) External oblique
4) Deltoid
11) Rectus abdominus
5) Pectoralis major
6) Sartorius
7) Tibialis anterior
12) Quadriceps muscles
6
7
12
13
13) Gastrocnemius
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Section 11.2 Your Muscular System
1
The Muscular System
1) __________
2
8
3
4
5
8) __________
9
2) __________
3) __________
10
9) __________
11
10) __________
4) __________
11) __________
5) __________
6) __________
7) __________
12) __________
6
7
12
13
13) __________
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Section 11.2 Your Muscular System
Frontalis
26
31
27
28
29
32
33
34
Sartorius
35
30
Gastrocnemius
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Section 11.2 Your Muscular System
Keeping Healthy
• You can maintain a healthy muscular system by
regularly participating in different types of exercise.
• To help prevent injuries, exercise sessions should
include a warm-up and cool-down period.
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Section 11.2 Your Muscular System
Working Your Muscles
• Some types of exercise increase a muscle’s
endurance—how long it can contract without tiring.
• Other exercises make individual fibers grow, which
causes the muscles to thicken and increase in
strength.
• Anabolic steroids - are artificial forms of the male
hormone testosterone.
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Section 11.2 Your Muscular System
Avoiding Muscle Injuries
• Strains - A muscle strain, or a pulled muscle, is a
painful injury that may happen when muscles are
overworked or stretched too much or too quickly.
• Tendonitis - Overuse of tendons may lead to painful
swelling and irritation called tendonitis.
• Prevent injuries
• regular strengthening and stretching exercises
• vary your exercise routine
• warm up and cool down
• stop exercising if you feel a sharp or sudden pain
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Section 11.2 Your Muscular System
Preventing Muscle Cramps
• A muscle cramp is a strong, uncontrolled muscle
contraction.
• To relieve a cramp, try massaging the affected area
and exercising the limb gently.
• Stretching and drinking plenty of water before and
during exercise can help you avoid muscle cramps.
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Section 11.2 Your Muscular System
Questions
1.
Identify 3 types of muscle and describe location and function of
each.
2. What is a tendon?
3. Explain what causes muscle tone?
4. What causes the condition known as atrophy?
5. What can you do to prevent muscle injuries?
6. What is the cause of a muscle strain?
7. Why is it an advantage that you do not have control over all of
your muscles?
8. Describe how a muscle pair in your thigh would work to bend and
then straighten your knee.
9. What type of muscle helps your to move your jaw to chew food?
10. Name an exercise that builds muscle endurance.
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