Edema occurs when blood pressure exceeds the counteracting force of in the bloodstream, so fluid remains in the spaces surrounding cells and body tissue swells.

Edema occurs when blood pressure exceeds the counteracting force of the vascullar walls in the bloodstream, so fluid remains in the spaces surrounding cells and body tissue swells.

Explanation:

The intravascular hydrostatic pressure increases due to an increase in fluids, therefore the vessel walls begin to perceive this increase in pressure in their walls, generating fluid extravasion to areas of lower pressure.

vascular walls in the bloodstream

Explanation:

Edema is the accumulation of fluid in the extracellular or interstitial space, in addition to the body's cavities. It is a sign that appears in many diseases and manifests itself as a swelling of the soft tissues due to the accumulation of fluid in the interstitial compartment. This edema can be seen locally as it happens in the lower extremities or as a generalised feeling of swelling (hands, abdomen).

Edema occurs if there is an imbalance between the forces that regulate the passage of fluid from one compartment to another. If there is abundant water flow from the intravascular to the interstitial compartment, an edema occurs. Such fluid extravasation may respond to physical or chemical factors, from an increase in intravascular pressure in the return circulation, to an increase in the permeability of the vascular wall, or a decrease in the levels of molecules that maintain intravascular fluid, caused by proteins.

So an edema is produced by an imbalance in the forces that regulate the passage of fluid from one compartment to another in the tissues.