Muscle Physiology

Which ions bind to troponin to move tropomyosin away from actin?

• Fluorine ions

• Calcium ions

• Potassium ions

• Sodium ions

What role does tropomyosin play in the muscular system?

• Tropomyosin covers myosin, blocking the ability of myosin to attach to actin

• Tropomyosin moves troponin out of the way, allowing for myosin to attach to actin

• Tropomyosin covers actin, blocking the ability of myosin to attach to actin

• Tropomyosin holds troponin in place, allowing for myosin to attach to actin

A person’s actin molecules are covered with excess tropomyosin. How will the position of tropomyosin affect muscle contraction?

• Tropomyosin will inhibit troponin from attaching to myosin

• Tropomyosin will help troponin attach to myosin

• Tropomyosin will help myosin attach to actin

• Tropomyosin will inhibit myosin from attaching to actin

Which connective tissue surrounds the fascicles?

• Perimysium connective tissue

• Endomysium connective tissue

• Areolar connective tissue

• Epimysium connective tissue

The A-band of a sarcomere contains dark striations. These striations come from which muscle fibre(s)?

• Actin only

• Myosin only

• Actin and myosin

• None of the above

Which structure is found at the ends of each sarcomere?

• I-band

• H-band

• Z-line

• A-band

Which of the following must occur to signal a muscle contraction?

• ADP must be produced

• Sodium ions must bind to troponin

• The sarcoplasmic reticulum must release acetylcholine

• An action potential must reach a muscle cell

What is the most effective way to increase the rate of muscle contraction?

• Decreasing calcium levels

• Increasing the amount of troponin

• Increasing calcium levels

• Increasing the amount of tropomyosin

• Decreasing the amount of acetylcholine

Which branch of the nervous system works most closely with skeletal muscles?

• Sympathetic nervous system

• Motor nervous system

• Autonomic nervous system

• Parasympathetic nervous system

When muscle contracts upon stimulation, calcium ions bind to __________, which exposes the binding sites for the myosin cross‐bridges to attach to.

• Actin

• Myosin

• Troponin