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Process in which the muscle fiber develops tension and may shorten–Thin filaments slide over thick filaments and pull the Z discs they are attached to; causing sarcomere to shorten01/06/188
Skeletal Muscle Contraction: Detailed•Contraction–Myosin binds to an exposed active site on the thin filament (actin)–Binding of thick and thin filaments is called CROSS - BRIDGE –Myosin head releases energy and flexes, “tugging” the thin filament along…called the POWER STROKE–When myosin binds another ATP, it is released from the thin filament–The process of cross-bridge and power stroke continues as long as calcium is present in the sarcoplasm and ATP is present01/06/189
Skeletal Muscle Contraction: Detailed•Relaxation–When the muscle fiber relaxes and returns to its resting length–Achieved when muscle cell stops receiving signal to contract–So when ACh is cleaved off from their receptors–Once this happens, calcium is pulled back into sarcoplasmic reticulum and is removed from troponin –This causes tropomyosin to cover up actin’s “active site”–Muscle returns to its resting length with the help of elastic components01/06/1810
Objectives01/06/1812•Describe the process of the sliding filament model of muscle contraction•Identify the necessary substances needed for muscle contraction and their individual role within muscle contraction