4. MUSCULAR SYSTEM Smooth Muscle Found in the digestive, circulatory, urinary and reproductive systems Controlled by the autonomic nervous system Smooth in appearance Involuntary controlled
12. SKELETAL MUSCLE ANATOMY Skeletal muscle is made up of fibres: Made up of smaller myofibrils Within each myofibril are strands of myofilaments (actin and myosin) Fibres grouped together are called fasciculi Fasciculi are then grouped together to form the muscle
13. SKELETAL MUSCLE ANATOMY Endomysium – surrounds each muscle fibre Perimysium – surrounds each fasciculi Epimysium – covers entire muscle
14. fascia surrounds the muscle connected to periosteum (bone) Epimysium the outer layer perimysium around each bundle offibres endomysium around each muscle fibre muscle fibre myofibril muscle filament SKELETAL MUSCLE ANATOMY
15. SLIDING FILAMENT THEORY Myofilamentsactin (thin) and myosin (thick) do not decrease in length when a muscle contracts. They simply slide over each other thus shortening the entire muscle. The myosin filaments have golf club shaped heads which attach onto the actin and pull the actin closer together (as detailed in picture on next slide)
16. SLIDING FILAMENT THEORY myosin actin myosin cross-bridges attach to the actin filaments actin is pulled together and sarcomere length is reduced
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18. NEUROLOGICAL SYSTEM The Central Nervous System The Brain and Spinal Cord The Peripheral Nervous System
19. THE REFLEX ARC Central Nervous System Sensory Receptor Sensory Nerve Motor Nerve Muscle responds to nerve impulses
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21. ‘All or none law’ – when a motor neuron is stimulated, ALL of the muscle fibres are activated
22. The more motor units that are recruited for a task, the greater the force will be developed