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

How does Myosin contribute to muscle function?

1. Stores calcium ions

2. Generates force and movement

3. Protects muscles from damage

4. Facilitates oxygen transport

The correct answer is: Generates force and movement

Myosin plays a crucial role in muscle function by generating force and movement. It is a motor protein that interacts with actin filaments within muscle cells to facilitate contraction. When a muscle is stimulated, myosin heads bind to actin and perform a power stroke, effectively pulling the actin filaments inward. This action shortens the muscle fiber, leading to muscle contraction and ultimately enabling movement. In the context of muscle physiology, myosin's ability to change shape and exert force is a fundamental aspect of the sliding filament theory. This theory explains how muscles contract through the sliding of actin and myosin filaments past each other, which is essential for any form of muscular activity, from voluntary movements to involuntary reflexes. While the other options mention important functions in the body, they do not pertain directly to the role of myosin in muscle contraction. For example, calcium ions are crucial for initiating the contraction process but are primarily stored in the sarcoplasmic reticulum and not associated with myosin directly. Protection from damage and oxygen transport are functions involving different structures and proteins; the former typically involves connective tissues and other types of muscle proteins, while the latter is handled by hemoglobin in red blood cells. Thus, myosin's