The complement system has a set of plasma proteins that enhance nonspecific and specific immune responses. They are secreted in an inactive form and activated where they are needed. Others form a coat on foreign cells that attracts phagocytes. Late components form large proteins that disrupt membranes and kill foreign cells. The purpose if inflammation is to destroy invaders and restore tissues to normal.
Inflammation occurs in both non-specific and specific defense responses.
They circulate in the blood stream. Release of histamine Histamine dilates blood vessels and causes seepage of fluid into tissues. Vasodilation causes warmth and redness. Seepage of fluid causes swelling. Phagocytes follow the chemical trail to damaged tissue and engulf invaders and cellular debris.