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The immune system is a complicated biological body system that protects us from pathogenic organisms such as bacteria, viruses and fungi which has cells that are from the hematopoietic stem cell in the bone marrow. It includes white blood cells, chemicals and proteins like complement proteins and antibodies. The system is divided into two major parts that is the innate immunity system (non-specific) and the adaptive system (specific). The innate plays a vital role in the system as it is the primary defence mechanism whilst the adaptive immune system is the second line of defence. All the types of the immune system involve cellular and humoral components which carry out protective functions. Cellular defences are used to differentiate whether an immune response is intervened by a certain type of cell. Cells such as the macrophages and the monocytes are involved with phagocytosis. These cells are all present in the myeloid lineage of the haematopoietic stem cells of the bone marrow. The stem cell is made up to two cells namely the myeloid progenitor and the lymphoid progenitor. The myeloid progenitor produces more dendritic, monocytes, neutrophils and basophils cells whereas the T and B cells are produced more in the lymphoid progenitor. Macrophages and dendritic cells play a vital role in the both types of immunity. These cells come from the mast cells and monocytes which are fixed tissues from the same cell as the circulating basophils. The B cells are found in the bone marrow and released into the lymphatic systems and blood. It develops into plasma cells and secretes antibodies. The T cells undergoes processes in the thymus where there are two types of cells being made, namely the CD4+ helper cells , and the CD8+ cytotoxi... ... middle of paper ... an endosome and connects with a lysosome which has acidic enzymes that kills and digests and forms a phagolysome. Unfortunately, this process does not always goes as planned because if the capsule of the pathogen is made out of complex sugars it would be hard to cling on to. For efficient binding with the phagocytes, the foreign pathogens need to be coated with complement proteins. This process is known as opsonisation. REFERENCES P.M. LYDYARD, A. WHELAN AND M.W. FANGE (2003) IMMUNOLOGY 2ND ED HOEHN K., MARIEB N. E. (2007) HUMAN ANATOMY & PHYSIOLOGY, SAN FRANCISCO, PEARSON INTERNATIONAL EDITION ABBAS K & LICHTMAN H. A. (2004) BASIC IMMUNOLOGY, SAUNDERS; 2ND EDITION WILLIAMS A. (2010) IMMUNOLOGY, JOHN WILEY & SONS INC
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