What is the normal blood pH range?

What is the normal blood pH range?

• A. 6.8-7.0
• B. 7.0-7.2
• C. 7.2-7.4
• D. 7.35-7.45

Answer: (D)

A stable pH is essential because enzyme activity and cellular processes depend on the proton concentration in blood. The body uses buffers, plus the quick adjustments of respiration and the slower adjustments of the kidneys, to keep pH in a very tight window. Normal arterial blood pH is about 7.35 to 7.45. Values below this range cause acidemia, while values above cause alkalemia; both situations disrupt metabolism and nervous system function. The range 7.35–7.45 reflects this normal, physiologic balance, whereas the other options fall outside the typical arterial reference range and would indicate acidemia or alkalemia. Remember, the pH scale is logarithmic, so even small shifts represent meaningful changes in hydrogen ion concentration.

A stable pH is essential because enzyme activity and cellular processes depend on the proton concentration in blood. The body uses buffers, plus the quick adjustments of respiration and the slower adjustments of the kidneys, to keep pH in a very tight window.

Normal arterial blood pH is about 7.35 to 7.45. Values below this range cause acidemia, while values above cause alkalemia; both situations disrupt metabolism and nervous system function. The range 7.35–7.45 reflects this normal, physiologic balance, whereas the other options fall outside the typical arterial reference range and would indicate acidemia or alkalemia. Remember, the pH scale is logarithmic, so even small shifts represent meaningful changes in hydrogen ion concentration.