Capillary Filtration and Tissue Fluid Formation

Steps:

• Identify Starling's hypothesis: hydrostatic pressure exceeds oncotic pressure at arterial end, causing net fluid filtration.
• Locate arrows in diagram: outward arrows indicate filtration from capillary lumen to interstitial space.
• Match to tissue fluid: formation occurs via this outward flow, not reabsorption.
• Confirm A as the arrow depicting this process.

Why A is correct:

• A shows outward flow from capillary, aligning with hydrostatic pressure driving filtration per Starling's forces.

Why the others are wrong:

• B indicates inward flow, representing reabsorption at venous end.
• C points to blood flow within capillary, not fluid exchange.
• D shows osmotic pull, which opposes formation.

Final answer: A