1.  The Immune System Neekoli Caulderon, Zoë Irons, Kori McEvoy, 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  Physical barriers  Mucous membranes  1 st line of defense 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)

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  Response to injury/infection  Localized redness, swelling, heat, pain  Result of blood vessel dilation and  Edema : increase in capillary permeability 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

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  3 rd line of defense against pathogens  Built up slowly over time  Resistance to specific pathogens or to other toxins Cells  Lymphocytes and macrophages that recognize & remember specific foreign molecules

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

10. Lymphocytes T Cells  Mature in the thymus  Have no antigen-presenting properties  Rely on B cells to mark a pathogen w/ antigens  70-80% of lymphocytes 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

11. Types of T Cells Cytotoxic T Cells  Kill cells infected with a virus ( apoptosis )  Kill (potential) cancer cells  Have been linked to organ transplant rejection 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

12. Cytotoxic T Cells

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

14. The End

15.  For Now