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Troponin controls the position of tropomyosin on the thin filament, enabling myosin heads to bind to the active sites on actin.
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∙ 12y ago
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Which molecules are involved with regulation of cross bridge attachment activity?
calcium ions, troponin, and tropomyosin
When does cross bridge cycling end?
cross bridge cycling ends when sufficient calcium has been actively transported back into the SR (to allow calcium to unbind from troponin)
What blocks the myosin binding sites on the actin molecule preventing cross bridge formation?
The tropomyosin molecule blocks the active sites of the actin. Troponin is a molecule that is bound to the tropomyosin. Troponin needs CA+ (calcium ions) to bind to it in order to rotate the tropomyosin molecule and expose the actin molecules for the myosin heads to interact for muscle contraction.
Cross-bridge formation that results in muscle contraction requires intracellular?
the major intracellular ion in crossbridge formation is what
What best describes the events of excitation in excitation-contraction coupling?
cross bridge formation "Excitation-contraction coupling" connects muscle fiber excitation to the muscle fiber contraction (cross bridge formation). During contraction, myosin heads form cross bridges many times-with each cross bridge generating a small amount of tension in the muscle fiber.
What describes the events of contraction in excitation-contraction coupling?
cross bridge formation "Excitation-contraction coupling" connects muscle fiber excitation to the muscle fiber contraction (cross bridge formation). During contraction, myosin heads form cross bridges many times-with each cross bridge generating a small amount of tension in the muscle fiber.
What is the actin status to begin cross bridge formation?
The actin binding sites are exposed
How are troponins I and T different?
cardiac troponin I tests measure only cardiac troponin; tests for cardiac troponin T may cross-react with troponin found in other muscles and give positive or increased results in the absence of heart damage.
What are chemical changes that are occurring during latent period?
Acetylcholine binds to sarcolemma; sarcolemma then T-tubules depolarize; Ca++ released from terminal cisternae travels along SR, is release into sarcoplasm, then binds to troponin to unblock tropomyosin binding sites allowing cross-bridge formation (i.e., myosin heads bind to actin).
How would the loss of acetylcholinesterase from the motor end affect skeletal muscle?
Acetylcholine release is necessary for skeletal muscle contraction, because it serves as the first step in the process, enabling the subsequent cross-bridge formation. A muscle's ability to contract depends on the formation of cross-bridges between myosin & actin filaments. A drug that blocks acetylcholine release would interfere with this cross-bridge formation and prevent muscle contraction
What does calcium bind to priot to cross-bridging?
Actin changes shape.
What is the process of excitation contraction coupling?
cross bridge formation "Excitation-contraction coupling" connects muscle fiber excitation to the muscle fiber contraction (cross bridge formation). During contraction, myosin heads form cross bridges many times-with each cross bridge generating a small amount of tension in the muscle fiber.
