PHYSIOLOGY
SYNAPTIC PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Which of the following statements concerning the role of Ca2+ in the contraction of skeletal muscle is correct?
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The mitochondria act as a store of Ca2+ for the contractile process
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Ca2+ entry across the plasma membrane is important in sustaining the contraction of skeletal muscle
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A rise in intracellular Ca2+allows actin to interact with myosin
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The tension of a skeletal muscle fibre is partly regulated by G proteins.
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Explanation:
Detailed explanation-1: -Which of the following best describes the role of Ca2+ in muscle contraction? It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.
Detailed explanation-2: -During muscle contractions, actin filaments slide over myosin filaments resulting in shortening of a sarcomere. So the correct answer is ‘Length of A− band remains constant’.
Detailed explanation-3: -A. Smooth muscle cells contract in response to an extracellular inward-Calcium-current. The sarcoplasmic reticulum in smooth muscle is only slightly developed so most of the calcium ions that cause contraction enter the muscle cell from the extracellular fluid at the time of the action potential.
There is 1 question to complete.