2. ACh is broken down by square 3. Calcium ions flood the square and bind to square Without calcium, what would happen? square 4. Muscle contractions start with a square , thin filaments are pulled toward the center of the square 5. Place in order: Calcium binds to troponin square Muscle Action Potential ACh hinds to recentors

2. ACh is broken down by acetylcholinesterase.<br />3. Calcium ions flood the sarcoplasmic reticulum and bind to troponin.<br />Without calcium, muscle contraction would not occur.<br />4. Muscle contractions start with a muscle action potential, thin filaments are pulled toward the center of the sarcomere.<br />5. Place in order:<br />ACh binds to receptors<br />Muscle Action Potential<br />Calcium binds to troponin