Muscular System Muscles for Locomotion
Engage • Tennis Ball Muscle Activity
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.
Explore • “Multitalented Muscles” Web Search
Explain • What are some functions of the Muscular System? • Contract and relax to move the body. • Stores energy • Protects internal organs
Two Muscle Categories • Involuntary • NOT under conscious control • Voluntary • Under conscious control
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…
Three Types of Muscles • Smooth Muscle • Cardiac Muscle • Skeletal Muscle
Smooth Muscle • Where lining of Internal Organs and Blood Vessels • Involuntary • Non striated • Function Squeeze, exert pressure by slow and prolonged contractions
Cardiac Muscle • Where Heart • Involuntary • Striated and branched
Skeletal Muscle • Majority of muscle in the body • Voluntary • Striated • Found attached to the skeleton by TENDONS.
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.
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
Functional Unit of Muscle • Sarcomere • Section of myofibril
Cycle Diagram 1 Myosin forms cross-bridge with actin 5 2 Myosin returns to original shape Cross-bridge changes shape 4 3 Cross-bridge releases actin Actin pulled
Cycle Diagram 1 Myosin forms cross-bridge with actin 5 2 Myosin returns to original shape Cross-bridge changes shape 4 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
Figure 36-11 Opposing Muscle Pairs Section 36-2 Movement Movement Biceps (relaxed) Biceps (contracted) Triceps (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
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
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)
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.