What term describes the swelling of blood vessels due to fluid accumulation?

The term that describes the swelling of blood vessels due to fluid accumulation is edema. Edema occurs when excess fluid builds up in the tissues, leading to swelling in various parts of the body. This condition can result from various factors such as inflammation, injury, or heart failure, where the balance of fluid regulation in the body is disturbed.

Anemia refers to a condition characterized by a deficiency of red blood cells or hemoglobin, which affects the body's ability to transport oxygen but is not related to fluid accumulation in blood vessels. Ischemia is a term that indicates a lack of blood flow to a particular area, leading to a shortage of oxygen and nutrients, but it does not imply swelling due to fluid. Thrombosis involves the formation of a blood clot within a blood vessel, obstructing blood flow, rather than fluid accumulation causing swelling. Thus, the correct answer, edema, specifically addresses the issue of swelling due to fluid build-up.