Immune System PDF

Collection of organs, cells, tissues & molecules that mediate the immune response protects body from outside invaders germs such as bacteria, viruses, & fungi, & toxins...

Collection of organs, cells, tissues & molecules that mediate the immune response protects body from outside invaders germs such as bacteria, viruses, & fungi, & toxins (chemicals made by microbes)  IMMUNITY Body’s specific protective response to foreign agent or organism; resistance to diseae specifically infectious diseases Parts of the immune system white blood cells antibodies complement system lymphatic system spleen bone marrow thymus.  Bone marrow spongy tissue found inside bones produces RBC, platelets, WBC Lymphocytes are produced in the marrow, & play an important part in the body's immune system White blood cells key players in the immune system made in the bone marrow & part of the lymphatic system ▼ move through blood & tissue throughout the body, looking for foreign invaders such as bacteria, viruses, parasites & fungi ▼ launch an immune attack White blood cells - lymphocytes B-cells T-cells natural killer cells) other types of immune cells  Antibodies help the body fight microbes or the toxins (poisons) they produce. ▼ Substance that recognizing substances called induces production of antigens on the surface of the antibodies microbe, or in the chemicals they produce, mark the microbe or toxin as foreign. ▼ mark these antigens for destruction. many cells, proteins & chemicals are involved in this attack  Complement system made up of small proteins found in the blood ▼ made by the liver ▼ Help or complement the work of antibodies, phagocytic cells ▼ to clear pathogens from an organism. Lymphatic system a network of delicate tubes throughout the body main roles : manage fluid levels in the body react to bacteria deal with cancer cells deal with cell products that would result in disease or disorders. absorb some fats in diet from the. intestine. The lymphatic system is made up of: lymph nodes ( lymph glands) – which trap microbes lymph vessels carry lymph - colourless fluid that bathes the body's tissues & contains WBC  a blood-filtering organ that removes microbes contains WBC destroys old, damaged RBC makes disease-fighting components of the immune system (antibodies & lymphocytes) RED PULP WHITE PULP Old, injured RBC are destroyed Contains lymphocytes  filters & monitors blood content. small gland in the It produces the lymphatic system that WBC called T- makes & trains lymphocytes special WBC called T- cells -- help immune system fight disease & infection.  The body's other defenses against microbes skin lungs waterproof barrier mucous in the lungs (phlegm) traps secretes oil with foreign particles bacteria-killing small hairs (cilia) wave the mucous properties upwards so it can be coughed out other defenses digestive tract body fluids : skin oil, saliva, tears mucous lining contains contain anti-bacterial enzymes antibodies The constant flushing of the urinary acid in the stomach can tract & the bowel kill most microbes  TYPES OF IMMUNITY: A. B. NATURAL IMMUNITY First line of host defense following antigen exposure, because it protects the host without remembering prior contact ▼ Production of cytokines, other Cell involved effector molecules Monocytes, macrophages, dendrite cells ▼ Natural killer cells – basophils, eosinophils, Activate cells to control granulocytes pathogens or promote ▼ development of acquired Release cell mediators histamine, immune respnse bradykinin, prostaglandins ▼ phagocytosis Macrophages tissue-resident or infiltrated immune cells critical for innate immunity, normal tissue development, homeostasis, & repair of damaged tissue classified as to function 1. classically-activated (M1) macrophages, 2. wound-healing macrophages or alternatively-activated (M2) macrophages 3. regulatory macrophages (Mregs). INFLAMMATORY RESPONSE major function of natural immune system A type of immunity that develops when a person's immune system responds to a foreign substance or microorganism, or that occurs after a person receives antibodies from another source  RESPONSE TO INVASION 1. PHAGOCYTIC IMMUNE RESPONSE Phagocytosis is a specific form of endocytosis by which cells internalize solid matter, including microbial pathogens 3 main groups of phagocytes: monocytes macrophages, Granulocytes dendritic cells Dendritic cells A special type of immune cell found in tissues, such as the skin, & boosts immune responses by showing antigens on its surface to other cells of the immune system.  2. HUMORAL IMMUNE RESPONSE (ANTIBODY RESPONSE) is mediated by antibody molecules secreted by plasma cells deals with antigens from pathogens that are freely circulating, or outside the infected cells. ▼ Antibodies produced by the B cells will bind to antigens, ▼ neutralizing them, or causing lysis (dissolution or destruction of cells by a lysin) or phagocytosis.  3. CELLULAR IMMUNE RESPONSE Cell-mediated immune responses involve the destruction of infected cells by cytotoxic T cells, or the destruction of intracellular pathogens by macrophages T cells part of the immune system & develop from stem cells in the bone marrow (migrate thymus for development)  TYPES OF T LYMPHOCYTES 1. Effector T cells key players in steering the immune responses to execute immune CD8 T lymphocytes – cytotoxic killer cells functions. ▼ T HELPER CELLS Directly attack antigen by CD4+ - T HELPER CELLS ▼ CD8+ - CYOTOXIC CELLS Altering cell membrane -(Cell lysis disintegraton) ▼ Releasing cytolytic enzymes, cytokines.CD4 T lymphocytes ▼ ▼ Activate other lymphocytes, WBC Secrete cytokines ▼ ▼ DESTROYING ORGANISM Attract/activate/coordinate B cells, cytotoxic T cells, NK cells, macrophages 2. Suppressor T-cells prevent hypersensitivity on OTHERS exposure to non-self cells or proteins which help to prevent NULL LYMPHOCYTES immune overreactions Destroy antigen already ▼ coated by antibody Decrease B cell production at a healthy level NATURAL KILLER CELLS Recognize infected ,stressed 3. Memory T cells cells antigen-experienced cells ▼ that mediate a faster & more Secrete macrophage potent response upon repeat activating cytokine encounter with antigen. ▼ Killing these cells