Microbiology

Microbiology Study Guide

©2018 of 132 The components of the complement system react with each other on a continuous basis and encourage the production of new substances that further lead to the components of reaction in the complement system. The output of this cascade of reactions is the production of many substances that prove toxic to the microorganism and thereby destruct the microbial membranes. In the complement system, two pathways are likely to exist: the classical pathway and the alternative pathway. The classical pathway is specific in nature and is initiated only when the antibodies in the immune system fuse with the antigen, which stimulates the complement system. In contrast, the alternative pathway is non-specific in nature and is initiated only when there is interference by the components of the cell wall of bacteria, tumors, and other organisms. In this pathway, the protein properdin plays a vital role. This is a comparatively slower method to eliminate the parasites and microorganisms from the body system. Mechanism of Phagocytosis The microorganism becomes phagocytosable through the process of opsonization, in which they coat themselves with the layer of proteins that are produced in the body and circulate in the plasma. The outcomes of phagocytosis of microorganisms can range from killing off the microorganisms after ingestion, or they may continue to survive. The organism could even continue to grow within the phagocytic cell. The outcome of the phagocytosis of microorganism depends on the nature of the organism and the phagocytic cell. Inflammation When the individual suffers from an injury due to the localized area of infection or physical injury of the tissue resulting from infectious substances released by microorganisms from chemicals released by the chemical mediators in the tissues, the tissue is likely to respond to these injuries. One such response is termed inflammation. In the process of inflammation, the arterioles and venules are dilated, which causes the flow of the blood in the body to increase, leading to warmth and redness over the body surface. Further, the endothelial cell junctions in the post-capillary venule open up and encourage the proteins in the plasma cells to migrate to the body tissues. Finally, the endothelial cells of the post-capillary venule attach themselves to the leukocytes, and the phagocytes, polymorphonuclear leukocytes (neutrophils), and mononuclear phagocytes migrate in body tissue. Individual, Species, and Racial Immunities There are several types of immunity that are more specific to groups and individuals. Individual immunity is a form of natural immunity that is unique and rare, and is not shared by the other family members in the species. The immunity is ignited by the incision of the infection, which is generally not recognized at the time of its occurrence. Species immunity involves diseases that will affect one species but not affect another. Racial immunity refers to a disease that will affect one race but not another. Achieve Page 57