Phagocytosis Discussion Capillary permeability is a very important concept. As permeability increases, the space between the endothelial cells increases, allowing more fluid, proteins, cells and other materials to leak out or move out into the surrounding tissue. Many substances involved in the inflammatory response increase capillary permeability, for example, histamine, SRSA and so on. This allows for wbc and other substances to penetrate the tissue where antigen is often located, but it can have consequences. It can lead to swelling and the loss of fluid from the intravascular space.
Inflammation is usually a localized event .
Swelling is due to the accumulation of fluid in the tissue, redness is due to increased blood flow to the area, pain is due to the action of bradykinin and prostaglandins on local nerve tissue and heat is due to increased blood flow to the area. However, inflammation can often have systemic effects. For example, fever. Fever is triggered when the hypothalamus's set point is changed by the action of cytokines. The cytokines reponsible are interleukin- 1, interleukin 6 and tumor necrosis factor.