In a laboratory experiment you have treated a muscle cell with a calcium channel blocker. The membrane still depolarizes, but the concentration of calcium never increases in the cytosol. Which of the following describes what will happen next?

A. Contraction will occur, but the muscle will be stuck in the contracted state and unable to relax.
B. Tropomyosin will continue to cover the myosin binding sites on actin and no cross-bridges will form.
C. Only one cross-bridge cycle will occur but no second cycle. 
D. Binding of myosin to actin will take place.
E. A single twitch in skeletal muscle but no sustained contraction.


Answer: B

Anatomy & Physiology

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