Emergency Medical Technician (EMT) Intermediate Practice Exam

If the concentration of H+ increases, what happens to the pH of the blood?

1. It increases

2. It decreases

3. It remains unchanged

4. It becomes neutral

The correct answer is: It decreases

The concentration of hydrogen ions (H+) is inversely related to pH. The pH scale is logarithmic, meaning that each whole number change on the scale represents a tenfold change in acidity or alkalinity. Specifically, as the concentration of hydrogen ions in a solution increases, the pH decreases, indicating a more acidic environment. In the context of blood, when the concentration of H+ rises, the body becomes more acidic, and as a consequence, the pH value drops from its normal range (around 7.35 to 7.45). This decrease in pH can have significant physiological effects, impacting enzyme activity, oxygen transport, and overall metabolic processes. The pH can indicate the body's acid-base balance, and an increase in H+ concentration suggests a shift towards acidosis. Understanding this relationship is crucial in emergency medical situations since changes in blood pH can be indicative of underlying conditions or imbalances that require prompt medical attention.