Muscular System Muscles for Locomotion
4/25/2014
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… April 25, 2014
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 April 25, 2014
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. April 25, 2014
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
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 April 25, 2014
Skeletal Muscle Structure
Functional Unit of Muscle Sarcomere – Section of myofibril
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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
4
Cross-bridge changes shape
3 Cross-bridge releases actin
Actin pulled
Muscle Contractions
April 25, 2014
Cycle Diagram
1 Myosin forms cross-bridge with actin 5
2 Myosin returns to original shape
4
Cross-bridge changes shape
3 Cross-bridge releases actic
Actin pulled
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 April 25, 2014
Figure 36-11 Opposing Muscle Pairs Section 36-2
Movement
Movement Biceps (relaxed)
Triceps (contracted)
Biceps (contracted)
Triceps (relaxed)
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 April 25, 2014
Regular Exercise Improves functioning of muscles Aerobic training can affect a muscle’s 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 world’s 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. April 25, 2014
