Emergency Medical Technician (EMT) Intermediate Practice Exam

At what pH level does cellular function deteriorate and death occur?

1. Below 7.0 or above 8.0

2. Below 6.9 or above 7.8

3. Below 6.5 or above 7.5

4. Below 7.2 or above 7.2

The correct answer is: Below 6.9 or above 7.8

Cellular function is highly dependent on the body's acid-base balance, which is reflected in the pH level of the blood and other bodily fluids. Generally, a normal pH range for human blood is between 7.35 and 7.45. When the pH level falls below 7.35 or rises above 7.45, it indicates acidosis or alkalosis, respectively. At a pH level below 6.9 or above 7.8, vital biochemical processes start to break down significantly. Enzymatic reactions, which are crucial for cellular metabolism, may not occur effectively outside this range, leading to deterioration of cellular functions. Severe deviation from this normal range triggers systemic physiological reactions that can be life-threatening, resulting in cell damage and ultimately leading to death if not corrected. Thus, the range specified in the correct answer accurately reflects the critical thresholds at which cellular function begins to fail, marking the importance of maintaining pH within a narrow and tightly regulated range for survival.