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The Immune System

The Immune System. Neekoli Caulderon , Zoë Irons, Kori McEvoy , Matt Noel. The Purpose of the Immune System. Prevent the entry of pathogens or Destroy them as they enter via innate (nonspecific) defenses or adaptive (specific) defenses

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The Immune System

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  1. The Immune System NeekoliCaulderon, Zoë Irons, KoriMcEvoy, Matt Noel

  2. The Purpose of the Immune System Prevent the entry of pathogens or Destroy them as they enter via innate (nonspecific) defenses or adaptive (specific) defenses Pathogen: disease causing agent including viruses, bacteria, fungi, & protozoans

  3. Nonspecific Defenses Mechanical Barriers Chemical Barriers Stomach acid (pepsin & HCl) Salt in sweat Interferons (respond to viruses/tumor cells) Complement (group of proteins in bodily fluids that interact in a series of reactions that stimulate inflammation,attracts phagocytes & enhances phagocytosis) • Physical barriers • Mucous membranes • 1st line of defense • Skin

  4. Leukocytes- White Blood Cells • Move in/out of capillaries via diapedesis • Lymphocytes: T-Cells, B-Cells, NK Cells • Phagocytes: cells that eat invading cells • Neutrophils: phagocytes that can move around quickly but immediately die after eating a cell and turn into pus • Macrophages: phagocytes that don’t move around quickly but can eat more than neutrophils; also detect cancerous cells

  5. Natural Killer (NK) Cells • Different from those that provide specific defenses • Defend the body against viruses and cancer cells by secreting cyclotic (cell-cutting) substances called perforins • Cause inflammation

  6. Inflammation and Phagocytosis Inflammation Phagocytosis Performed by phagocytes which are attracted to chemicals released by injured tissues Powerful mechanism that effectively destroys a lot of pathogens before we know they’re there • Response to injury/infection • Localized redness, swelling, heat, pain • Result of blood vessel dilation and • Edema: increase in capillary permeability

  7. Fever • Elevated body temperature • Causes liver and spleen to store iron, reducing its level in the blood • Bacteria and fungi require more iron as temperature rises, so their growth and reproduction is slowed • Phagocytes are more active at a higher temperature • Not always meant to be treated with a lot of medication

  8. Specific/Adaptive Immune System Immunity Cells Lymphocytes and macrophages that recognize & remember specific foreign molecules • 3rd line of defense against pathogens • Built up slowly over time • Resistance to specific pathogens or to other toxins

  9. Antigens/Antibodies Antigens Antibodies AKA Immunoglobulin Produced by memory B cells that recognize the antigen Y-shaped Bind with specific antigens, tagging the pathogen for elimination • Incite the production of antibodies & the immune response • Come from invading pathogens • Molecule or protein given off by pathogens • A chemical fingerprint

  10. Lymphocytes T Cells B Cells Immature cells produced in bone marrow, become transitional B cells before maturing Produce antibodies that destroy antigens/antigen-bearing agents 20-30% of lymphocytes • Mature in the thymus • Have no antigen-presenting properties • Rely on B cells to mark a pathogen w/ antigens • 70-80% of lymphocytes

  11. Types of T Cells Cytotoxic T Cells Memory T Cells Present in blood stream for an extended duration after the infection has subsided React quickly to a triggering antigen upon re-exposure • Kill cells infected with a virus (apoptosis) • Kill (potential) cancer cells • Have been linked to organ transplant rejection

  12. Cytotoxic T Cells

  13. In Summary • http://youtu.be/CeVtPDjJBPU

  14. The End

  15. For Now

  16. Immune Responses Primary Secondary After Primary response B cells become memory cells • 1st immune response to antigen • Leads to generation of memory cells • Humoral response

  17. Allergic Reactions • An immune response to a non-harmful substance • Allergens: antigens that trigger allergic reactions • Delayed-reaction allergy: repeated exposure of skin to certain chemicals • Immediate-reaction allergy: inherited tendency to overproduce IgE antibodies in response to certain allergens

  18. Autoimmunity • Immune system fails to distinguish self from nonself • Produces autoantibodies that attack and damage tissues and organs

  19. Autoimmunity Autoimmune Diseases Reasons the Immune System may Attack Itself  T cells never learned to identify foreign cells from body cells Non-self antigen resembles a self antigen A virus borrows proteins from host cell’s surface while replicating,so… The body learns to attack the virus in order to destroy it but also learns to attack the human cells • Type I Diabetes • Rheumatoid Arthritis • Systemic Lupus Erythematosus

  20. The Actual End

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