Inflammation is the body’s natural defense against injury or disease. The body also uses this process to repair tissue after an injury has taken place. The special cells that take part in inflammation are called inflammatory cells and they are part of the body’s immune system.
Inflammation is divided into two stages. The first stage is called acute inflammation. This stage starts shortly after the injury has occurred and usually only lasts for a couple days. However, this stage can continue for a longer period of time if the reason for the injury or disease persists. For example, acute inflammation caused by an infection can continue as long as the micro-organism causing the infection is still in the body. In some areas of the body, pathologists use the word active to describe this stage.
Types of immune cells that take part in this stage include neutrophils and eosinophils.
The second stage is called chronic inflammation. Not all injuries or diseases will cause chronic inflammation. When this stage does occur, it usually starts just as the acute inflammatory stage is ending. This stage can last for days or weeks depending on the injury or disease.
While inflammation helps the body fight off disease and repair after an injury, the inflammatory response can also cause damage to nearby cells. Pathologists often describe cells damaged by the inflammatory process as showing reactive change.
Some diseases are caused by inflammation that continues for a long period of time. The inflammatory cells damage normal cells and tissue and this prevents the organ from functioning properly.