Chapter 1_Structure and Function of Exercising Muscle

Ca²⁺ ions are stored in the

• Sarcoplasm

• Sarcolemma

• Sarcoplasmic reticulum

• T-tubules

Which protein is sensitive to Ca²⁺ and thereby helps initiate contraction?

• actin

• myosin

• troponin

• tropomyosin

Thick filaments are primarily made of which protein?

• actin

• myosin

• troponin

• tropomyosin

Type II muscle fibers are more fatigue resistant than type I muscle fibers

• True

• False

Compared to type I muscle fibers, type II muscle fibers are better at producing ATP via glycolysis

• True

• False

A muscle contraction is triggered by which ion?

• Na⁺

• K⁺

• Ca²⁺

• Cl^-

Which is the correct order of events in a contraction?

• Action potential travels down t-tubule, Ca²⁺ taken back up into SR, cross-bridge formation, Ca²⁺ released from SR

• Ca²⁺ released from SR, cross bridge formation, Ca²⁺ taken back up into SR, Action potential travels down t-tubules

• Cross-bridge formation, Ca²⁺ released from SR, Ca²⁺ taken back up in SR, Action potential travels down t-tubules

• Action potential travels down t-tubules, Ca²⁺ release from SR, cross-bridge formation, Ca²⁺ taken back up into SR

Which protein blocks the myosin-binding site, preventing contraction from happening at rest?

• actin

• myosin

• troponin

• tropomyosin