OSMT (Ontario Society of Medical Technologists) Practice Exam

Muscle fatigue is the result of the lack of __________ and the production of __________

1. Oxygen/glucose

2. Glucose/oxygen

3. Oxygen/lactic acid

4. Lactic acid/oxygen

The correct answer is: Oxygen/glucose

The correct answer focuses on the biochemical processes that occur during muscle fatigue. Muscle fatigue arises primarily due to the depletion of oxygen, which is essential for aerobic respiration. When exercises become intense and prolonged, the muscles require more energy, typically derived from glucose or glycogen breakdown. As oxygen becomes limited, the muscle cells switch from aerobic metabolism to anaerobic metabolism, which is less efficient and leads to the production of lactic acid as a byproduct. This accumulation of lactic acid can contribute to the sensation of muscle fatigue. The correct pairing identifies the two central aspects of fatigue: a lack of oxygen (needed for aerobic energy production) and the consequent production of lactic acid during anaerobic energy production. In this context, the other options do not accurately represent the underlying biological reasons for muscle fatigue. For instance, while glucose is an important energy source, the lack of oxygen is the primary factor leading to anaerobic metabolism and lactic acid production.