A 7-year-old boy punctures his thumb with a rusty nail. Four hours later, the thumb appears red and swollen. Initial swelling of the boy’s thumb is primarily due to which of the following mechanisms?
Decreased intravascular hydrostatic pressure
|B.||Decreased intravascular oncotic pressure|
|C.||Increased capillary permeability|
Increased intravascular oncotic pressure
Answer :C Increased capillary permeability
Forces that regulate the balance of vascular and tissue fluids include
(2) oncotic pressure
(3) osmotic pressure,
(4) lymph flow.
During inflammation, an increase in the permeability of the endothelial cell barrier results in local edema.
Vasodilation of arterioles exacerbates fluid leakage, and vasoconstriction of postcapillary venules increases the hydrostatic pressure in the capillary bed potentiating the formation of edema.
Vasodilation of venules decreases capillary hydrostatic pressure and inhibits the movement of fluid into the extravascular spaces.
Acute inflammation is not associated with changes in plasma oncotic pressure