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Lecture 10


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Lecture 10

  1. 1. 4. MONOCYTES * Exit blood (diapedesis) to become macrophages * 2-6 % of the WBC's * Phagocytic = defend against viruses and bacteria
  2. 2. Life span of WBC <ul><li>The life of granulocytes is normally 4 to 8 hours in the blood and another 4 – 5 days in tissue where they needed </li></ul><ul><li>The monocytes 10 – 20 hours in the blood and in the tissues they become larger size and become tissue macrophage </li></ul><ul><li>Lymphocytes have life span weeks or months depends on the needs </li></ul>
  3. 3. Leukocyte <ul><li>Leukocyte (WBC) are the mobile units of the body protective system </li></ul><ul><li>They are formed in the bone marrow (granulocytes and monocytes and few lymphocytes) and in the lymph tissue (lymphocytes) </li></ul><ul><li>Leukocytes work in two ways to prevent disease </li></ul><ul><li>Destroying invading bacteria/viruses by phagocytosis </li></ul><ul><li>By forming antibodies </li></ul>
  4. 4. <ul><li>Five types of WBC </li></ul><ul><li>Three types of the cells are polymorphonuclear cells. All have granular appearance </li></ul><ul><li>The granulocyte and monocytes protect the body against invading organism by phagocytosis </li></ul>Leukocyte
  5. 5. <ul><li>Human being has about 7000 WBC /micro liter </li></ul><ul><li>Normal percentage are </li></ul><ul><li>Neutrophils 62% </li></ul><ul><li>Eosinphils 2.3% </li></ul><ul><li>Basophils 0.4% </li></ul><ul><li>Monocytes 5.3% </li></ul><ul><li>Lymphocytes 30% </li></ul>Leukocyte
  6. 6. <ul><li>Neutrophils and Monocytes (macrophages) attack the invading bacteria, viruses </li></ul><ul><li>WBC can squeeze through the blood capillaries by diapedesis </li></ul><ul><li>WBC can move by ameboid motion </li></ul><ul><li>WBC are attracted to inflamed tissue area by Chemotaxis </li></ul>Leukocyte
  7. 7. <ul><li>Phagocytosis which means cellular ingestion of the offending agent </li></ul><ul><li>Macrophages are much more powerful phagocytes than neutrophils </li></ul><ul><li>Lysosome in the neutrophil and macrophage come in contact with the phagocytic vesicle and digestion of phagocytized particles begin </li></ul><ul><li>Both neutrophils and macrophages contain proteolytic enzyme. The lysosome in the macrophages contain lipases </li></ul>Leukocyte
  8. 8. Neutrophils and macrophages kill bacteria <ul><li>Neutrophils and macrophages contains oxidizing agent such as H 2 O 2 which is lethal to most bacteria </li></ul>
  9. 9. Monocyte-Macrophage Cell System <ul><li>The combination of monocytes, mobile macrophages, fixed tissue macrophages and specialized endothelial cells in the bone marrow, spleen and lymph nodes is called Monocyte-Macrophage cell system or reticuloendothelial system </li></ul>
  10. 10. Tissue macrophage in the skin <ul><li>Once the skin broken, infection occur and inflammation ensues </li></ul><ul><li>Macrophages in subcutaneous tissue (Histiocyte) destroy the infectious agent by performing phagocytosis </li></ul>
  11. 11. Macrophages in the lymph nodes <ul><li>Large numbers of macrophages line the lymph sinuses and if any particles enter the sinuses the macrophages phagocytize them </li></ul>
  12. 12. Alveolar macrophages in the lungs <ul><li>Invading organisms enter the body through the lungs </li></ul><ul><li>Tissue macrophages are present as integral components of alveolar walls </li></ul><ul><li>They can phagocytize particles that entrapped in the alveoli </li></ul>
  13. 13. Macrophages Kupffer cells in the liver sinusoids <ul><li>Bacteria invading the body from ingested food through gastrointestinal tract into the portal blood </li></ul><ul><li>Blood passes through sinusoids of the liver which lined with tissue macrophages called Kupffer cells </li></ul><ul><li>These cells form such an effective particulate filtration to prevent passing bacteria from the gastrointestinal tract to the blood circulation system </li></ul>
  14. 14. Macrophages of the spleen and bone marrow <ul><li>Macrophages of the spleen and bone marrow is another defense against organism that succeeded to enter the blood circulation </li></ul>
  15. 15. <ul><li>Inflammation is the body response to infection or injury. The functions of inflammation are to destroy or inactivate foreign invaders and to set stage for tissue repair </li></ul>Inflammation
  16. 16. Inflammation <ul><li>Vasodilation of the blood vessels with consequent excess blood flow </li></ul><ul><li>Increased permeability of the capillaries allowing leakage of large quantity of fluid </li></ul><ul><li>Often clotting of the fluid </li></ul><ul><li>Migration of large numbers of granulocytes and monocytes into the tissue </li></ul><ul><li>Swelling of the tissue cells </li></ul><ul><li>Some products that cause these reaction are histamine, serotonin and prostaglandins </li></ul>
  17. 17. <ul><li>The first result of inflammation is to “wall-off” the area of injury from the remaining tissue. </li></ul><ul><li>The intensity of the inflammatory process is proportional to the degree </li></ul><ul><li>Staphylococci release lethal toxins Inflammation </li></ul><ul><li>Rapid Wall Off </li></ul><ul><li>Streptococci no tissue destruction Inflammation </li></ul><ul><li>Slow Wall Off </li></ul>Effect of inflammation “walling-off”
  18. 18. <ul><li>Within few minutes after inflammation begins, tissue macrophages begins their phagocytic action. </li></ul><ul><li>Many fixed tissue macrophages break loose from their attachment forming the first line of defense against infection </li></ul>Macrophage and Neutrophil Responses During Inflammation
  19. 19. <ul><li>Neutrophil invasion of the inflamed area is the second line of defense </li></ul><ul><li>Neutrophils begins to invade the inflamed area from the blood </li></ul><ul><li>This is caused by products from the inflamed area which initiate the following reactions: </li></ul><ul><li>Alter the inside surface of the capillary causing neutrophils stick on the capillary walls. This called margination </li></ul><ul><li>Caused intracellular attachment to loosen diapedesis </li></ul><ul><li>Other product caused chemotaxis </li></ul>Macrophage and Neutrophil Responses During Inflammation
  20. 20. <ul><li>Second macrophages invasion is a third line of defense </li></ul><ul><li>Monocyte from the blood enter the inflamed tissues and enlarged to become macrophages </li></ul><ul><li>Macrophages can phagocytize more bacteria larger particles than neutrophils </li></ul>Macrophage and Neutrophil Responses During Inflammation
  21. 21. <ul><li>Increased production of granulocytes and monocytes by bone marrow is the fourth line of defense </li></ul>Macrophage and Neutrophil Responses During Inflammation