A decrease in plasma albumin would alter capillary exchange by:

A decrease in plasma albumin would alter capillary exchange by:

• A. Increasing colloid osmotic pressure and edema will vanish
• B. Decreasing colloid osmotic pressure and edema will occur
• C. No effect
• D. Increasing hydrostatic pressure

Answer: (B)

Capillary exchange is driven by Starling forces: hydrostatic pressure pushes fluid out of capillaries, while colloid (oncotic) pressure pulls fluid back in due to plasma proteins like albumin. If plasma albumin decreases, the colloid osmotic pressure inside vessels drops, so less fluid is reabsorbed into the capillaries. The net effect is increased filtration relative to reabsorption, causing fluid to accumulate in the interstitial space and leading to edema. This is why the correct outcome is decreased colloid osmotic pressure with edema occurring. Increasing colloid osmotic pressure would pull fluid back in and reduce edema, and hydrostatic pressure isn’t directly increased by low albumin, so those options don’t fit.

Capillary exchange is driven by Starling forces: hydrostatic pressure pushes fluid out of capillaries, while colloid (oncotic) pressure pulls fluid back in due to plasma proteins like albumin. If plasma albumin decreases, the colloid osmotic pressure inside vessels drops, so less fluid is reabsorbed into the capillaries. The net effect is increased filtration relative to reabsorption, causing fluid to accumulate in the interstitial space and leading to edema. This is why the correct outcome is decreased colloid osmotic pressure with edema occurring. Increasing colloid osmotic pressure would pull fluid back in and reduce edema, and hydrostatic pressure isn’t directly increased by low albumin, so those options don’t fit.