OSMT (Ontario Society of Medical Technologists) Practice Exam

The correct answer highlights myoglobin as the protein that can store oxygen within muscle tissues. Myoglobin is a globular protein similar in structure to hemoglobin, which is found in red blood cells, but it serves a distinct function. Myoglobin has a high affinity for oxygen and is designed to store oxygen in muscle cells, allowing for a ready supply of oxygen during periods of increased muscle activity. While hemoglobin is responsible for transporting oxygen from the lungs to various tissues throughout the body, myoglobin acts more like a localized oxygen reservoir. It releases oxygen when muscle cells are in need, particularly during exercise when oxygen demand increases. This capacity for oxygen storage plays a crucial role in enhancing endurance in muscle function. The other protein choices listed do not have the primary function of storing oxygen. Myosin is involved in muscle contraction and is part of the thick filaments in muscle fibers. Troponins are regulatory proteins that help to control muscle contraction but do not bind or store oxygen. Thus, myoglobin stands out as the correct answer for oxygen storage within fibers.