1. IMMUNE SYSTEM I NON-SPECIFIC DEFENSE PP. 957-960

2. FUNCTION Fights pathogens to prevent infections and disease Works with the lymphatic system (collects fluid and returns it to the blood)

3. KOCH’S POSTULATES Study page 957

4. STRUCTURES Bone marrow: produces blood cells Lymphocytes: wbc Thymus: mature wbc Lymph nodes: stores wbc Spleen: contains wbc that clean out pathogens as blood filters through

5. WHITE BLOOD CELLS (wbc) Also called leukocytes Type of wbc present indicates specific disease or have specific job IE. Neutrophils respond to bacteria

6. INITIATING THE IMMUNE SYSTEM pathogens: cause disease - viruses: protein shell containing DNA or RNA - bacteria, protists, fungi

7. FIRST LINE OF DEFENSE Skin: block entry mucous membranes: trap pathogens and move them out of the body stomach acids: destroys pathogens

9. SECOND LINE OF DEFENSE Inflammatory response 1. Injured cells release a chemical signal called histamine to increase blood flow to area 2. platelets cause clotting trapping pathogens 3. Area swells, becomes warm, and macrophages/phagocyte (wbc) move in and engulf bacteria

10. interferons: enzymes that stop virus protein production fever: increase activity of wbc