Which is a TRUE statement about excitation-contraction coupling?

Question

Quizplus · Accepted Answer

Calcium-induced calcium-release is a process in which the initial release of calcium from the sarcoplasmic reticulum triggers further release of calcium from adjacent channels, amplifying the signal. This occurs in cardiac muscle cells and some smooth muscle cells, but not in skeletal muscle cells. Option A is incorrect because in skeletal muscle cells, calcium ions are stored in the sarcoplasmic reticulum and are released when an action potential depolarizes the membrane. Option B is incorrect as smooth muscle cells have a different mechanism of excitation-contraction coupling that does not involve action potentials. Option C is incorrect because while calcium entry is required in some types of muscle cells, it is not necessary in all. Option E is incorrect as an action potential propagates along the sarcolemma, not the sarcoplasmic reticulum membrane.

Which Is a TRUE Statement About Excitation-Contraction Coupling