Question

8. Here is a jumbled summary of steps involved in muscle contraction. Put them into correct order in the following chart, and then place the number for each step in the correct location on the preceding diagram. • Calcium ions bind to troponin molecules of thin filaments. • Acetylcholine is released from synaptic vesicles. Adapted from Pearson Publishing Active Reading Chapter 50 Skeletal Muscle • Acetylcholine binds to receptors on the muscle fibers. This allows Na+ ions to rush, causing depolarization. • The troponin/tropomyosin complex is moved so the myosin-binding site of actin is exposed. • Depolarization continues across the sarcolemma and down the transverse tubule system. • Ca++ is released from cisterns of the SR (sarcoplasmic reticulum). • Nerve impulse arrives at the neuromuscular junction. • Myosin heads rotate, bind the actin, and pull the actin fibers toward the center of the sarcomere. • In the presence of Ca++, myosin acts as an enzyme. It catalyzes breakdown of ATP. Energy is transferred from ATP to the myosin head; myosin is activated. Steps of Muscle Contraction Steps of Muscle Contraction 1. 2. 3. 4. 5. 6. 7. 8. 9.

          8. Here is a jumbled summary of steps involved in muscle contraction. Put them into correct order in the following chart, and then place the number for each step in the correct location on the preceding diagram.

• Calcium ions bind to troponin molecules of thin filaments.
• Acetylcholine is released from synaptic vesicles.

Adapted from Pearson Publishing

Active Reading Chapter 50 Skeletal Muscle

• Acetylcholine binds to receptors on the muscle fibers. This allows Na+ ions to rush, causing depolarization.
• The troponin/tropomyosin complex is moved so the myosin-binding site of actin is exposed.
• Depolarization continues across the sarcolemma and down the transverse tubule system.
• Ca++ is released from cisterns of the SR (sarcoplasmic reticulum).
• Nerve impulse arrives at the neuromuscular junction.
• Myosin heads rotate, bind the actin, and pull the actin fibers toward the center of the sarcomere.
• In the presence of Ca++, myosin acts as an enzyme. It catalyzes breakdown of ATP. Energy is transferred from ATP to the myosin head; myosin is activated.

Steps of Muscle Contraction
Steps of Muscle Contraction
1.
2.
3.
4.
5.
6.
7.
8.
9.

8. Here is a jumbled summary of steps involved in muscle contraction. Put them into correct order in the following chart, and then place the number for each step in the correct location on the preceding diagram.

• Calcium ions bind to troponin molecules of thin filaments.
• Acetylcholine is released from synaptic vesicles.

Adapted from Pearson Publishing

Active Reading Chapter 50 Skeletal Muscle

• Acetylcholine binds to receptors on the muscle fibers. This allows Na+ ions to rush, causing depolarization.
• The troponin/tropomyosin complex is moved so the myosin-binding site of actin is exposed.
• Depolarization continues across the sarcolemma and down the transverse tubule system.
• Ca++ is released from cisterns of the SR (sarcoplasmic reticulum).
• Nerve impulse arrives at the neuromuscular junction.
• Myosin heads rotate, bind the actin, and pull the actin fibers toward the center of the sarcomere.
• In the presence of Ca++, myosin acts as an enzyme. It catalyzes breakdown of ATP. Energy is transferred from ATP to the myosin head; myosin is activated.

Steps of Muscle Contraction
Steps of Muscle Contraction
1.
2.
3.
4.
5.
6.
7.
8.
9.

Added by Denise C.

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