Muscular System

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Muscular System

• Muscles for Locomotion

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Engage

• Tennis Ball Muscle Activity

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Explore

• Chicken Wing Dissection
• The major function of the muscular system is to
  support our body in movement. Through
  observations and class discussion, you will make
  deduction about certain principles of muscle
  function.

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Explore

• Multitalented Muscles
• Web Search

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Explain

• What are some functions of the Muscular System?
• Contract and relax to move the body.
• Stores energy
• Protects internal organs

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Two Muscle Categories

• Involuntary
• NOT under conscious control
• Voluntary
• Under conscious control

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Think About It!!

• Can you think of one body function that you
  perform without thinking about it?
• Breathing, Heart Beating, Digestion, etc
• How about one that one must think about?
• Picking up a pencil, walking, running, etc

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Three Types of Muscles

• Smooth Muscle
• Cardiac Muscle
• Skeletal Muscle

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Smooth Muscle

• Where? lining of Internal Organs and Blood
  Vessels
• Involuntary
• Non striated
• Function? Squeeze, exert pressure by slow and
  prolonged contractions

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Cardiac Muscle

• Where? Heart
• Involuntary
• Striated and branched

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Skeletal Muscle

• Majority of muscle in the body
• Voluntary
• Striated
• Found attached to the skeleton by TENDONS.

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Questions

• What are the two categories of muscles?
• What are the three types of muscles?
• Muscle that contract under conscious control are
  _________.
• ______ attaches muscle to bone.

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Skeletal Muscle Structure
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Skeletal Muscle Structure

• Muscle - made of bundles
• Bundles- many muscle fibers
• Muscle Fiber many myofibrils
• Myofibrils- filaments (thick or thin)
• Thick filaments myosin protein
• Thin filaments actin protein
• Thick and Thin give striated look

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Skeletal Muscle Structure
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Functional Unit of Muscle

• Sarcomere
• Section of myofibril

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Muscle Contractions
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Cycle Diagram
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Myosin forms cross-bridge with actin
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2
Myosin returns to original shape
Cross-bridge changes shape
3
4
Cross-bridge releases actin
Actin pulled
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Muscle Contractions
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Cycle Diagram
1
Myosin forms cross-bridge with actin
5
2
Myosin returns to original shape
Cross-bridge changes shape
3
4
Cross-bridge releases actic
Actin pulled
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Muscle Attachment to Bone

• Muscles attached to bone by tendons.
• Muscles are attached in opposing pairs.
• One Muscle contracts to raise the limb, while the
  second will contract to lower it.
• Bicep / Triceps

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Figure 36-11 Opposing Muscle Pairs
Section 36-2
Movement
Movement
Biceps (relaxed)
Biceps (contracted)
Triceps (contracted)
Triceps (relaxed)
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Muscle Strength and Exercise

• Strength DOES NOT depend upon the number of
  fibers. Why?
• Born with all fibers we will have.
• Depends on the THICKNESS of fibers and how many
  contract at one time

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Muscle Soreness After Exercise

• Do muscle cells need O2?
• Yes!!!
• Do muscle cells need ATP?
• Yes!!!
• Working out moderately provides us enough oxygen
  (aerobic) to change glucose into ATP
• Called _________ respiration
• Working out rigorously does not allow us to get
  enough O2 in our blood. What happens with no O2
  (anaerobic)?
• Lactic Acid Fermentation
• Lactic Acid builds up in muscle cells passes into
  the blood stream, causes the blood to become
  acidic, stimulates breathing, and can cause
  cramping

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Regular Exercise

• Improves functioning of muscles
• Aerobic training can affect a muscles ability to
  share and use energy
• Increases endurance and thickness of muscle
  filaments (strength)

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Elaboration

• The Universe Within
• Watch the coordination of several different body
  systems and how they make Mike Powell the worlds
  greatest long jumper.
• Muscle Builders!
• Using various materials, you will build a model
  that simulates muscle contractions and
  relaxations. This model depicts one muscle
  working in isolation, but as we have learned,
  muscles in the body cooperate in a group effort,
  like in the chicken wing.