INTRODUCTION: At the beginning of the inflammatory process, cells move out of the vessels into the area of inflammation recruited by chemotactic agents. Inflammatory cells become activated and then can phagocytized offending materials, in a process that occur in steps as follows.
MARGINATION AND ROLLING OF WBCS: Moving from axial flow to the margin of the vessels is called margination. Marginated leukocytes begin to roll on the endothelial surface by forming transient adhesion molecules via the selectin family of proteins: In that respect, E-selectin on endothelial cells, P-selectin on endothelial cells and platelets and L-selectin on leukocytes. Selectins bind oligosaccharides that decorate mucin-like glycoproteins. Adhesion to endothelium occurs via selectins and integrins.
MIGRATION OF LEUCOCYTES: Passage of the cells across the wall of blood vessels, and moved to reach the site of inflammation by the effect of chemical mediators gradient (chemotaxis). Chemotaxis is a process resulting from certain products of WBCs, platelets, and microorganisms, which attracts WBCs towards the inflammation area according to the high concentration of that substance.
PHAGOCYTOSIS: This is defined as the engulfment and internalization of foreign bodies which maybe bacteria, viruses and others, in the phagosome and digestion of this substance. Phagocytosis is a process whereby cells ingest solid particles. The first step in phagocytosis is adhesion of the particle to be phagocytesed to the cell surface. Then the phagocyte ingests the attached particle by sending out pseudopodia around it. Then met and fused so that the particle lies in a phagocytic vacuole (called a phagosome) then bounded to small bodies containing enzymatic compounds called lysosomes, to form phagolysosomes. In which intracellular killing of microorganisms occurs. Phagocytic cells include neutrophils, polymorph nuclear cells, eosinophils, and monocytes.
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