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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
Goals/Objectives
Describe the functions of the three types of
muscles.
Explain how you can keep your muscular system
healthy.
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Key Terms
Muscular System
The body system that consists of muscles that
provide motion and maintain posture.
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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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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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Voluntary vs Involuntary Muscles

• Voluntary muscle is a muscle that a person can
  control.
• Involuntary muscle is a muscle that functions
  without a persons control.

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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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Muscle Pairs
Biceps contracted
Triceps relaxed
Biceps relaxed
Triceps contracted
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Tendons

• A thick strand of tissue called a tendon attaches
  a muscle to a bone.

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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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The Muscular System
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1) Frontalis
8) Biceps
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2) Temporalis
9) Triceps
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3) Trapezius
10) External oblique
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4) Deltoid
11) Rectus abdominus
5) Pectoralis major
12) Quadriceps muscles
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6) Sartorius
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13) Gastrocnemius
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7) Tibialis anterior
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The Muscular System
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1) __________
8) __________
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2) __________
9) __________
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3) __________
10) __________
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4) __________
11) __________
5) __________
12) __________
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6) __________
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13) __________
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7) __________
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Frontalis
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Sartorius
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Gastrocnemius
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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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Working Your Muscles

• Some types of exercise increase a muscles
  endurancehow 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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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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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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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.