Net filtration pressure at capillary arteriole end

Steps:

• Recall Starling's equation: Net pressure = (Pc + πi) - (Pi + πp), where Pc is capillary hydrostatic pressure, πp is plasma oncotic pressure, Pi is interstitial hydrostatic pressure, πi is interstitial oncotic pressure.
• At arteriole end, Pc ≈ 3.3 kPa (high due to arterial inflow); Pi ≈ 0 kPa; πp ≈ 2.1 kPa; πi ≈ 0 kPa.
• Simplify: Net pressure ≈ Pc - πp = 3.3 - 2.1 = 1.2 kPa (positive value drives fluid out).
• Confirm direction: Positive net pressure causes filtration out of capillary.

Why C is correct:

• Matches Starling's net filtration pressure calculation (3.3 kPa hydrostatic minus 2.1 kPa kPa outward).

Why the others are wrong:

• A: Negative value indicates reabsorption, incorrect for arteriole end where hydrostatic dominates.
• B: Underestimates net by ignoring precise standard values (too low at +1 kPa).
• D: Overestimates by using only hydrostatic pressure without subtracting oncotic (+5.2 kPa too high).

Final answer: C