What directly blocks cross bridge interaction between actin and myosin in skeletal muscle?

Question

Quizplus · Accepted Answer

Tropomyosin is a protein that blocks the myosin-binding site on the actin filament, preventing cross bridge formation and muscle contraction. Acetylcholine is a neurotransmitter that initiates muscle contraction by leading to the release of calcium ions. Z lines are simply the boundaries between the sarcomeres and also do not directly block cross bridge interaction. Calcium ions are required for cross bridge formation, not blockage.

What Directly Blocks Cross Bridge Interaction Between Actin and Myosin