Emergency Medical Technician (EMT) Intermediate Practice Exam

What happens during anaerobic metabolism due to cellular ischemia?

1. Oxygen levels increase in the cells

2. Blood stagnates in the capillaries and lactic acid is produced

3. Carbon dioxide is expelled more effectively

4. ATP production increases in cells

The correct answer is: Blood stagnates in the capillaries and lactic acid is produced

During anaerobic metabolism due to cellular ischemia, the lack of sufficient oxygen dramatically alters how cells generate energy. When the blood supply to a tissue is compromised, cells are unable to perform aerobic respiration, which relies on oxygen to produce adenosine triphosphate (ATP), the energy currency of cells. Instead, the cells revert to anaerobic metabolism, which does not require oxygen and produces ATP in much lower amounts. In this anaerobic process, glucose is converted to energy through glycolysis, resulting in the formation of pyruvic acid. However, because oxygen is lacking, pyruvic acid is then converted to lactic acid. This buildup of lactic acid can lead to acidosis within the cells and the surrounding tissues, which can contribute to further cellular dysfunction and damage. Additionally, because the blood flow is impaired, this process can lead to stagnation of blood in the capillaries and a lack of effective waste removal, exacerbating the situation. Understanding this metabolic process is crucial for EMTs when assessing and treating conditions related to ischemia, as timely intervention can help restore oxygen supply and prevent cellular injury.