阿摩線上測驗
4. Which of the following is a fundamental physiological difference between cardiac and skeletal muscle that prevents tetanic contractions in cardiac muscle?
(A) Cardiac muscle lacks functional T-tubules, preventing rapid excitation-contraction coupling.
(B) Cardiac muscle action potentials involve L-type Ca2+ channels, prolonging depolarization and refractory periods.
(C) The sarcoplasmic reticulum in cardiac muscle lacks ryanodine receptors, preventing sustained Ca2+ release.
(D) The pacemaker activity of cardiac muscle ensures a fixed contractile frequency, preventing summation.
(E) Cardiac muscle myosin has a significantly lower ATPase activity, preventing repeated cross-bridge cycling.
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統計： A(2), B(10), C(0), D(7), E(0) #3421109
統計： A(2), B(10), C(0), D(7), E(0) #3421109
