THE IMMUNE SYSTEM Chapter 40 (Miller & Levine)

Transcription

1 THE IMMUNE SYSTEM Chapter 40 (Miller & Levine)

2 40 1 Infectious Disease A. How Diseases Are Spread 1. Vectors animals that carry disease-causing organisms from person to person (ticks, mosquitos, other humans, etc.) 2. Sexually transmitted diseases syphilis & gonorrhea bacteria hepatitus B & C, genital herpes, AIDS, Ebola - virus Fighting Infectious Diseases prevention! Antibiotics kill bacteria w/out harming cells Antivirals inhibit virus s ability to invade & multiply inside cells

3 Immunity intro NONSPECIFIC IMMUNITY Rapid responses to a broad range of microbes SPECIFIC IMMUNITY Slower responses to specific microbes External defenses Internal defenses Invading microbes (pathogens) Skin Mucous membranes Secretions Phagocytic cells Antimicrobial proteins Inflammatory response Natural killer cells B-cells: Humoral response (antibodies) T-Cells: mediated response

4 Lymphatic System Adenoid Interstitial fluid Lymphatic capillary Tonsil Lymph nodes Blood capillary Spleen Peyer s patches (small intestine) Appendix Tissue cells Lymphatic vessel Lymphatic vessels Lymph node Masses of lymphocytes and macrophages

5 40 2 The Immune System Nonspecific Defenses like fortress walls keep everything out 1. First Line of Defense a. skin most important mucus sweat tears 2. Second Line of Defense a. inflammatory response reaction to tissue damage due to injury or infection; white blood cells enter infected tissues phagocytes eat bacteria b. immune system produces white blood cells when pathogens detected, so high white blood cell count = infection c. increase body temp. fever kills pathogens and helps white blood cells 3. Interferon group of proteins that resist viral infection and slows down infection

6 40 2 The Immune System Specific Defenses like security guard deals with specific invaders; substance that triggers specific immune response = antigen 1. Humoral Immunity in body fluids a. B lyphocytes ( B cells ) produce antibodies protein that destroys pathogens (bacterial & viral) b. B cells capable of producing slightly different antibody c. pathogen is recognized by sm. fraction of B cells, but then they quickly copy themselves & release antibodies into bloodstream d. activation & regulation of plasma cells is done by T-cells (helper cells) 2. Cell-Mediated Immunity a. killer T cells kill pathogen cells b. marker proteins on cells allow T-cells to recognize body cells & non-body cells 3. Permanent Immunity memory B & T cells remain able to produce specific antibodies to that pathogen after surviving disease

7 40 2 The Immune System 4. Active Immunity -vaccination weakened or mild form of pathogen -stimulates immune system to produce plasma cells ready to fight that pathogen 5. Passive Immunity -antibodies for pathogen from other animals put into bloodstream, then only last a short while until body destroys them (antibodies) -maternal immunity

8 Section 40-2 Primary and Secondary Immune Responses Antibody Concentration First exposure Interval between exposures Second exposure Time

9 Fig Pathogens and Disease Pathogen Types Viruses Bacteria Protists Worms Fungi Disease Common cold Influenza Chicken pox Measles Tuberculosis Meningitis Cholera Tetanus African sleeping sickness Malaria Amoebic dysentery Schistosomiasis Beef tapeworm Athlete s foot Ringworm Agent That Causes Disease Rhinovirus Two types (A, B), plus subtypes Varicella Paramyxovirus Mycobacterium tuberculosis Neisseria meningitidis Vibrio cholerae Clostridium tetani Trypanosoma Plasmodium Entamoeba histolytica Schistosoma Taenia saginata Imperfect fungi Imperfect fungi Method of Transmission Airborne; direct contact with infected person Airborne; droplet infection; direct contact with infected person Airborne; direct contact with infected person Droplets in air; direct contact with secretions of infected person Droplets in air; contaminated milk and dairy products Direct contact with a carrier Contaminated drinking water Contaminated wound; usually puncture wound Spread by tsetse fly Spread by Anopheles mosquitoes Contaminated drinking water Freshwater streams and rice paddies Contaminated meat Contact with infected person Exchange of hats, combs, or athletic head gear with infected person