Question

What is the pH range of extracellular fluid?

• A. \( \text{7.15 to 7.20} \)
• B. \( \text{7.25 to 7.30} \)
• C. \( \text{7.35 to 7.45} \)
• D. \( \text{7.50 to 7.60} \)

Hint:

Remember the "7.4" rule for blood pH — the normal extracellular fluid pH is tightly regulated between \(7.35\) and \(7.45\). Deviations outside this range can cause serious physiological effects.

Answer 1

The Correct Option is C

The pH of extracellular fluid (ECF), which includes blood plasma and interstitial fluid, is tightly regulated to maintain normal physiological functions.
The normal pH range of extracellular fluid is approximately\(\mathbf{7.35 \text{ to } 7.45}\).Values below 7.35 indicate acidosis, and values above 7.45 indicate alkalosis.This narrow range is crucial for proper enzyme activity, protein structure, and overall cellular processes.
The body maintains this pH via buffer systems such as the bicarbonate buffer system, phosphate buffer system, and protein buffers, along with respiratory (lungs) and renal (kidneys) regulation.