PHYSIOLOGY
SYNAPTIC PHYSIOLOGY
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Actin
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Myosin
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Troponin
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Tropomyosin
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Detailed explanation-1: -The calcium ions released from endoplasmic reticulum72) bind to the calcium-binding subunit of troponin (troponin-C (TnC), ∼18 kDa), and the inhibition by troponin is neutralized to trigger muscle contraction.
Detailed explanation-2: -Each heartbeat is triggered by a pulse of intracellular calcium ions which bind to troponin on the actin-containing thin filaments of heart muscle cells, initiating a change in filament structure that allows myosin to bind and generate force.
Detailed explanation-3: -1: Muscle contraction: Calcium remains in the sarcoplasmic reticulum until released by a stimulus. Calcium then binds to troponin, causing the troponin to change shape and remove the tropomyosin from the binding sites.
Detailed explanation-4: -Ca2+ binding to troponin initiates thin filament activation exposing myosin binding sites on actin. However, unlike in skeletal muscle, thin filament activation in cardiac muscle is not achieved primarily by Ca2+ binding alone (16, 17, 37).