Inflammation in action
Inflammation is a vital function of your innate immune system that is triggered immediately when it detects an invading pathogen or damaged tissue. Near the area of damage, the walls of tiny blood vessels called capillaries expand to bring more blood to the area. They also become more porous so that fluid, proteins, and white blood cells are allowed to migrate into the spaces between cells in the affected tissue—a necessary step to contain an infected area.
The area then quickly becomes hot, red, and swollen from the increased blood flow and fluid accumulation. Pressure from the fluid buildup and inflammatory molecules that are drawn to the area can irritate nerve fibers and lead to pain. As a result of these changes, the tissue in the inflamed area may not be able to function as it should. For example, you may not be able to walk if you have a twisted ankle, or swallow properly if you have a sore throat.
The final stage of the inflammatory process is termination and repair. Once the offending pathogen or substance has been eliminated, tissue repair begins. The surviving cells regenerate to replace damaged ones. Cells that are part of less complex structures, such as the surface of the skin, regrow easily. Cells in more complicated organs, such as the liver or glands, do not normally increase in number but may be prompted to do so after damage has occurred.
If it is impossible to regrow normal tissue at the site of the inflammation, scar tissue may form to fill in the deficits. However, if the threat remains and the immune response is constantly triggered—or an individual has a condition that is causing the immune system to react as if there is a threat—the inflammatory response can continue and damage the body instead of healing it.