PHYSIOLOGY
MUSCLE CONTRACTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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It is removed from the body
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It is used to build bone
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It is transported to the sarcoplasmic reticulum
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It binds to the sodium
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Detailed explanation-1: -Ca2+ binds with the protein participating in muscle contraction to induce muscle contraction and is then reabsorbed into the sarcoplasmic reticulum via Ca2+ ATPase.
Detailed explanation-2: -Abstract. In muscle cells, the excitation-contraction cycle is triggered by an increase in the concentration of free cytoplasmic Ca(2+). The Ca(2+)-ATPase present in the membrane of the sarcoplasmic reticulum (SR) pumps Ca(2+) from the cytosol into this intracellular compartment, thus promoting muscle relaxation.
Detailed explanation-3: -The action potential invades T-tubules and causes the L-type calcium channels to open, which in turn causes ryanodine receptors (RyRs) in the SR to open and release calcium, which stimulates contraction. Calcium is pumped back into the SR by (SR/ER calcium ATPase SERCA) pumps.
Detailed explanation-4: -Most of this calcium moves back and forth across the sarcoplasmic-reticulum membrane in cycles of contraction and relaxation. The channel responsible for release from the sarcoplasmic reticulum is the ryanodine receptor, whereas Ca2+-ATPase effects reuptake in an ATP-dependent manner.