File:IPLab3AcuteAppendicitis2b.jpg|This is a low-power photomicrograph of a normal appendix on the right and an this appendix with an acute inflammatory response on the left. Note the abundant focal areas of blue-stained lymphoid tissue beneath which is normal for the mucosal layer and the absence of blue-staining cells in normal appendix. Compare this with the submucosal layer increased size of the normal inflamed appendix(left) due to inflammatory cells and edema.File:IPLab3AcuteAppendicitis2x. Compare jpg|Photomicrograph of this appendix with acute inflammatory response. Note the extensive distribution of cells throughout the wall of the this appendix with acute appendicitis. The blue color is due to the presence of many inflammatory cells, although at this low power these individual cells cannot be specifically identified.File:IPLab3AcuteAppendicitis3b.jpg|This is a photomicrograph showing the serosal surface of the appendix with the layer of fibrinopurulent exudate noted in the gross photo (1). The muscularis (M) and the submucosa (S) also have a robust inflammatory cell infiltrate.