The inflammatory response occurs whenever the body tissues are physically traumatized. Trauma to body tissues could be intense heat, irritating chemicals, or infections from viruses. The inflammatory response has several benefits, it prevents the spread of harmful antigens to nearby tissues, disposes of cellular debris and pathogens, alerts the adaptive immune system, and helps prepare the body for repairs. Mast cells play a key role in the inflammatory response and release histamine into the intercellular fluid. Macrophages and other cells in the digestive and respiratory tract have receptors called toll-like receptors that recognize invaders and send out chemical alarm systems. . Some other chemicals involved in this process are kinins, prostaglandins, and compliment.