INFLAMMATION

INFLAMMATION
The inflammatory response (inflammation) occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. Chemicals including histamine, bradykinin, serotonin, and others are released by damaged tissue. These chemicals cause blood vessels to leak fluid into the tissues, causing swelling. This helps isolate the foreign substance from further contact with body tissues.
The chemicals also attract white blood cells that "eat" microorganisms and dead or damaged cells. The process in which these white blood cells surround, engulf, and destroy foreign substances is called phagocytosis, and the cells are called phagocytes. Phagocytes eventually die. Pus is formed from a collection of dead tissue, dead bacteria, and live and dead phagocytes.