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

To solve this problem, let's explore the pH range of extracellular fluid, which is critical for maintaining homeostasis in the body.

1. What is Extracellular Fluid?

Extracellular fluid (ECF) refers to all the fluid outside the cells in the body. It includes blood plasma, interstitial fluid, and other body fluids. The pH of extracellular fluid is tightly regulated to ensure proper cellular function, enzyme activity, and overall physiological balance.

2. Explanation of Each Option:

- Option 1: "7.15 to 7.20" – This is incorrect. The pH of extracellular fluid is not typically this low. A pH in this range would indicate a state of acidosis, which can be harmful to the body.

- Option 2: "7.25 to 7.30" – This is incorrect. Although this range is closer to the normal pH range, it still indicates acidosis, which is not the typical pH of extracellular fluid under normal physiological conditions.

- Option 3: "7.35 to 7.45" – This is the correct answer. The pH of extracellular fluid is normally maintained in the range of 7.35 to 7.45, which is slightly basic. This range is essential for maintaining optimal function of enzymes and cellular processes.

- Option 4: "7.50 to 7.60" – This is incorrect. A pH in this range would indicate alkalosis, which is not typical for extracellular fluid and could lead to various health problems if sustained.

3. Why This Matters:

Maintaining the pH of extracellular fluid within the normal range is essential for the proper functioning of metabolic processes. The body uses various buffering systems, including bicarbonate and proteins, to ensure that the pH remains stable within this narrow range.

4. Final Answer:

The correct pH range of extracellular fluid is 7.35 to 7.45.