1. Notes 11.7: Immune System Non-Specific defense
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2. Function Fights pathogens to prevent infections and disease
Works with the lymphatic system (collects fluid and returns it to the blood)

3. structures Bone marrow: produces blood cells
Lymphocytes: white blood cells (WBC)
Lymph nodes: stores WBC
Thymus: matures WBC
Spleen: contains WBC that clean out pathogens as blood filters through

4. Initiating the immune system
Antigen: any substance that the immune system responds to
Allergens: Cause allergies (pollen, dust mites, mold, etc.)

5. Initiating the immune system
Antigens continued
Pathogens: cause disease
Viruses: protein shell containing DNA or RNA
Bacteria
Fungi (spores)
Parasites
Toxins (snake bites etc)

6. Nonspecific defense
Protects body against any pathogen, regardless of the pathogen’s identity

7. First lines of defense Mucous membranes Skin Blocks entry
Sweat & oil are toxic to many pathogens
Mucous membranes
Mucous: traps pathogens

8. First lines of defense Cilia: moves pathogens out of body
Stomach acids: destroys pathogens

9. Second Line of defense: non-specific response
Inflammatory Response

10. Second Line of defense: non-specific response
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

11. Second Line of defense: non-specific response
Interferons: enzymes that stop virus protein production
Fever: hypothalamus sets a higher set point for body temperature, this slows growth of bacteria and increases activity of WBC
Should a fever always be treated? Why or why not?

12. Second Line of defense: non-specific response
White blood cells: there are many types, some act in a non-specific way, these WBC are called phagocytes

13. Second Line of defense: non-specific response
Types of phagocytes
Neutrophils: Ingest pathogens
Macrophage: Engulf pathogens & other cell debris
Natural Killer Cells: Burst pathogen infected cells