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Delve into the complexity of the muscular system, with over 600 muscles aiding in locomotion, blood pumping, breathing, and temperature regulation. Learn about skeletal, smooth, and cardiac muscles, their structures, functions, and movement mechanisms like muscle contraction. Discover how muscles work in pairs, hypertrophy, and atrophy effects, and test your knowledge with an interactive quiz.
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1. Muscle of the Body • Over 600 muscles in the human body • Functions • Locomotion • Pump blood • Breathing • Regulation of body temperature
2. Types of Muscle • Skeletal • Usually attached to bones • Voluntary movement (conscious control): moving bones, face, eyes, limbs, etc. • Striations, several nuclei
Smooth Muscle • Line the walls of internal organs: stomach, blood vessels, intestines • Involuntary movement (no neural input): move food, control blood flow, dilate pupils • Spindle-shaped, one nucleus
Cardiac Muscle • Found only in the HEART • Involuntary movement: movement of heart • Striated, usually only one nucleus • Strongest muscle
3. Structure of Skeletal Muscle • Muscle > bundle of muscle fibers > muscle fiber > myofibril > sarcomere > actin/myosin
Muscle Contraction • Need ATP heart rate and breathing rate increase due to increased need for oxygen • Sliding Filaments • Sarcomere: actin (thin) and myosin (thick) • Nerve signals: release neurotransmitters and Ca2+ rushes inside cell • Actin and myosin slide past each other sarcomere shortens muscle contracts
Movement • Muscles contract and relax • Work in opposing pairs • Exercise • Hypertrophy (addition of actin and myosin filaments) = increase in size • Atrophy = decrease in size = weaker • Astronauts
Quiz • Which of the following type of muscle is found in your stomach and intestines? • cardiac muscles • smooth muscle • striated muscle • Which muscles fibers are thicker? • actin • myosin • they are both thick • they are both thin.
What attaches muscles to bones? • tendons • ligaments • synovials • skin • Cardiac muscle is voluntary • true • false