Question:medium
Normal interstitial fluid hydrostatic pressure is?
Normal interstitial fluid hydrostatic pressure is?
Show Hint
Free interstitial fluid pressure is mildly subatmospheric, around -1 mmHg.
Updated On: Jun 24, 2026
- 10 to 15 mmHg
- -5 to 0 mmHg
- 20 to 30 mmHg
- -10 to -20 mmHg
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: Recall the four Starling forces that govern fluid movement across capillaries. One of these is the interstitial fluid hydrostatic pressure, measured in the free fluid of the tissue spaces surrounding the capillaries.
Step 2: In a normal, well drained tissue this pressure sits just under atmospheric level. The representative figure quoted in physiology is close to $-1$ mmHg, and tissue to tissue it spans roughly $-5$ mmHg to $0$ mmHg. Hence the matching option is -5 to 0 mmHg.
Step 3: Why negative and not positive? Lymphatic vessels actively pump fluid out of the interstitium, creating a mild suction that keeps the compartment slightly subatmospheric. If lymph drainage fails, the pressure rises toward positive values and oedema appears.
Step 4: Discarding distractors: 10 to 15 and 20 to 30 mmHg describe strongly positive pressures that do not occur normally, and -10 to -20 mmHg overstates the negativity seen in free interstitial fluid. Only the mildly negative band fits.
\[\boxed{-5 \text{ to } 0 \text{ mmHg}}\]
Step 2: In a normal, well drained tissue this pressure sits just under atmospheric level. The representative figure quoted in physiology is close to $-1$ mmHg, and tissue to tissue it spans roughly $-5$ mmHg to $0$ mmHg. Hence the matching option is -5 to 0 mmHg.
Step 3: Why negative and not positive? Lymphatic vessels actively pump fluid out of the interstitium, creating a mild suction that keeps the compartment slightly subatmospheric. If lymph drainage fails, the pressure rises toward positive values and oedema appears.
Step 4: Discarding distractors: 10 to 15 and 20 to 30 mmHg describe strongly positive pressures that do not occur normally, and -10 to -20 mmHg overstates the negativity seen in free interstitial fluid. Only the mildly negative band fits.
\[\boxed{-5 \text{ to } 0 \text{ mmHg}}\]
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