Inflammatory Response

Inflammatory Response. Before injury epithelial tissue separates the external environment or a body cavity from the underlying more delicate connective tissues and body organs. The connective tissue is nourished by the blood vessels and contains mast cells. The inflammatory response and wound healing occur simultaneously but are separate processes tha both begin immediately after injury. Stage 1 Injured cells release alarm chemicals. Injured calls at the injury site release chemokine alarm chemicals which travel to nearby cells. The concentration of chemokines is greatest at the injury site creating a concentration gradient. Mast cells are stimulated by the chemokine alarm chemicals to release histamine which causes nearby blood vessels to dilate and cause its capillaries in the area to become leaky increasing circulation and the build-up of fluid which manifests itself swelling. White blood cells begin to enter the area to help prevent infection. Stage 2 Circulation increase and fluid buildup. Platelets and clotting factors in the fluid help temporarily seal the injury and prevent the spread of infection. This begins the process of wound healing. White blood cell macrophages began consuming bacteria and viruses in the area guided by the concentration gradient of chemokine alarm chemicals coming for injured cells. Stage 3: Swelling decreases when tissue repair is complete Once the cells surrounding the injury are no longer damaged or under attack by pathogens they stop releaseing alarm signals. Circulation around the injury site returns to normal. The lymphatic system returns the excess fluid to the ciculatory system decreasing swelling.