1. Immune System The Body’s Defense System

2. Types of Pathogens: Agents that can cause disease… Viruses Bacteria Protists Worms Fungi

3. Nonspecific Defenses First Line of Defense –Skin, mucus, sweat and tears Second Line of Defense –Inflammatory Response Production of WBC Swollen tissue Fever Increase of Heart Rate Interferon release (if viral infection)

4. Immune Response When nonspecific defenses are surpassed, specific defenses start working. Antigens: Substance that triggers an immune response Lymphocytes –T Cells –B Cells

5. Humoral Immunity Specific defense against pathogens in BODY FLUID Antibodies –Attract cells to phagocytize (“eat”) the antigen –OR cause agglutination (clumping) –Contains antigen binding site

6. Cell-Mediated Immunity Defense against body’s own cells that have been infected by a pathogen. (INSIDE OF CELLS) T Cells –Develop in bone marrow –Mature in the Thymus –There are many types! “Killer” T Cells - KILL “Helper” T Cells- HELP “Suppressor” T Cells- WEAKEN “Memory” T Cells- REMEMBER

7. Allergies & Transplants Allergic Reactions –Mast cells- cause inflammation –Histamines- chemicals released by mast cells –Antihistamine- work against histamines –Asthma- narrowing of air passages Organ Transplants- Body sometimes recognizes organ as foreign and can “reject” transplant