College of Massage Therapists of British Columbia (CMTBC) Practice Exam

What function does Troponin serve in muscle tissue?

1. Assists in muscle relaxation

2. Regulates calcium binding and muscle contraction

3. Generates mechanical energy

4. Stores oxygen during exercise

The correct answer is: Regulates calcium binding and muscle contraction

Troponin plays a crucial role in muscle contraction by regulating the interaction between actin and myosin, the two primary proteins involved in muscle movement. It is a complex of three subunits that bind to calcium ions. When calcium is released into the muscle fibers, it binds to the troponin complex, causing a conformational change that moves tropomyosin away from the binding sites on actin. This shift exposes the sites where myosin heads can bind to actin, thereby initiating the contraction process. This function is essential for enabling muscles to contract effectively and is a key aspect of the excitation-contraction coupling in striated muscles. Therefore, the correct answer highlights troponin's pivotal role in regulating calcium binding and muscle contraction. Understanding how troponin works is fundamental for comprehending muscle physiology and the mechanisms that allow muscles to function properly.