Immune System Overview Flow Chart CA Biology Standards Physiology 10a & 10d

Physiology Standard 10b Students know the role of antibodies in the body’s response to infection.

Non-Specific Immunity Defenses that are NOT designed to fight a specific disease, but ALL diseases!! Chemical & Physical Barriers Include: 1. 1.Skin – Most important first line of defense. Physical barrier that keeps pathogens out! 2. 2.Mucus – Contains enzyme (lysosyme) that break down cell walls of many bacteria 3. 3.Sweat & Tears – Contains lysosyme and promote acidic environment that bacteria cannot survive

4. Inflammatory Response: A non-specific defense reaction to tissue damage caused by injury or infection. a. a.White Blood Cells (Phagocytes) – Detect, engulf and destroy pathogens b. b.Fever- Elevated body temperature kills or slows down growth of pathogens 5. Interferons- Proteins produced by virus- infected cells. Help other cells resist viral infections. What if the 1 st line of defense doesn’t do the job?

Specific Immunity Triggered by specific Antigens to produce Antibodies Triggered by specific Antigens to produce Antibodies – –Antigen – A foreign substance that triggers an immune response. Two Types of Responses: Two Types of Responses: 1.Humoral Response “Humoral” = In blood or lymph “Humoral” = In blood or lymph 2.Cell-Mediated Response

Humoral Response 1. 1.In the Blood & Lymph a. a.Lymphocytes produce antibodies 2. 2.Antibodies are Y-Shaped Proteins that help to destroy pathogens a. a.Pathogens are foreign threats to the body (virus, bacteria, etc) b. b.Antibodies bind to antigens on the pathogens c. c.Cause pathogens to clump up Antigen- binding sites Antigen Antibody

Humoral Response 3. 3.White blood cells engulf and destroy pathogens (clumps of antibodies & antigens) 4. 4.B cells can be activated by T cells to turn into plasma cells Plasma cells produce and release large numbers of antibodies into the bloodstream Some B cells become Memory Cells and can quickly respond if reinfected by same antigen (you can’t get the same cold twice)

Humoral Response

Cell-Mediated Response 1. 1.Killer T cells kill infected cells to inhibit the reproduction and spread of viruses Killer T cells are also called Cytotoxic T cells 2. 2.Causes body to reject transplanted organs

Cell-Mediated Response Macrophage T Cell Helper T Cell Killer T Cell Infected Cell Antigens are displayed on surface of macrophage T cell binds to activated macrophage T cell, activated by macrophage, becomes a helper T cell Helper T cell activates killer T cells and B cells Killer T cells bind to infected cells, disrupting their cell membranes and destroying them Figure 40-10

Vocabulary Pathogens Pathogens Viruses Viruses Bacteria Bacteria Antiseptics Antiseptics Antibiotics Antibiotics