1. 14 - 1 Chapter 14 The Lymphatic System & Immunity

2. 14-1: Anatomical Barriers  Pathogen  Pathogen—microorganisms that cause disease  Lymphatic system  Lymphatic system—cells, tissues, organs responsible for defending the body  Immunity  Immunity—ability to resist infection & disease  Innate (nonspecific) immunity  Innate (nonspecific) immunity protects against any pathogen  Adaptive (specific) immunity  Adaptive (specific) immunity attack specific pathogens

3. 14-1 Checkpoint 1.Define pathogen. 2.Explain the difference between nonspecific and specific defense. 14 - 3

4. 14-2: Lymphatic System Functions of the Lymphatic System lymphocytes  Produce, maintain & distribute lymphocytes  Most live many years  Return fluids from peripheral tissues to the bloodstream  Distribute hormones, nutrients, wastes from tissues to bloodstream 14 - 4

5. Lymphatic Vessels lymph  Carry lymph (tissue fluid) to venous system  Lymph contains fluids, solutes, pathogens 14 - 5  Lymphatic capillaries lymphatic ducts  Lymphatic capillaries  lymphatic vessels  lymphatic ducts

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7. Lymphocytes  T cells  T cells (most lymphocytes)  Cytotoxic T cells cellular immunity  Cytotoxic T cells directly attack foreign cells or virus-infected cells (provides cellular immunity)  Helper T cells  Helper T cells stimulate T cells & B cells  Suppressor T cells  Suppressor T cells inhibit T cells & B cells  B cells antibodies humoral immunity  B cells secrete antibodies that bind to specific antigens (provides humoral immunity)  NK cells  NK cells attack foreign cells, cancer cells

8. Lymphoid Nodules  Lymphoid nodules tonsils  Lymphoid nodules increase/decrease in size depending on number of lymphocytes present (ex: tonsils) Lymphoid Organs  Lymph nodes  Lymph nodes defend against bacteria & other invaders  Thymus  Thymus produces T cells  Spleen  Spleen filters blood, initiates B cell & T cell responses

9. 14-2 Checkpoint 1.List the components of the lymphatic system. 2.How would blockage of lymphatic ducts affect the circulation of lymph? 3.If the thymus gland failed to produce thymic hormones, which population of lymphocytes would be affected? 4.Why do lymph nodes enlarge during some infections?

10. 14-3: Innate (Nonspecific) Defenses  Deny entry or limit the spread of microorganisms or other hazards Physical Barriers  Keep hazardous organisms & materials from entering the body  Skin, mucous membranes, hair, sweat 14 - 10

11. Phagocytes  Phagocytes  Phagocytes attack & remove microorganisms  Microphagesmacrophages  Microphages & macrophages engulf invading pathogens Immunological Surveillance  Immunological surveillance  Immunological surveillance monitors normal tissues & attacks abnormal cells (uses NK cells) 14 - 11

12. Interferons  Interferons  Interferons released by lymphocytes to interfere with viral replication in cellsInflammation  Inflammation  Inflammation—localized tissue response to injury histamine heparin  Tissue damage  mast cells release histamine & heparin  redness, heat, swelling & pain  tissue repair 14 - 12

13. Fever  Fever  Fever increases body temperature  Benefits: increases metabolism, cells move faster, enzyme reactions proceed quicker, bacteria inactivated  Problems: high fevers damage body systems, damage nervous tissue, seizures 14 - 13

14. 14-3 Checkpoint 1.List the body’s nonspecific defenses. 2.A rise in the level of interferon in the body indicates what type of infection? 3.What effects does a fever have on the body?

15. 14-4: Adaptive (Specific) Defenses  Respond to presence of specific antigens cell-mediated immunity  T cells defend against abnormal cells & pathogens (cell-mediated immunity) antibody-mediated immunity  B cells defend against antigens & pathogens (antibody-mediated immunity) Types of Immunity  Innate immunity  Innate immunity present at birth 14 - 15

16.  Adaptive immunity  Adaptive immunity acquired by active or passive means  Active immunity  Active immunity appears after exposure to an antigen Naturally acquired active immunityNaturally acquired active immunity—exposure to antigens in environment Artificially induced active immunityArtificially induced active immunity—develops after immunizations (vaccinations)  Passive immunity  Passive immunity produced by the transfer of antibodies Naturally acquired passive immunityNaturally acquired passive immunity—mother’s breast milk Artificially induced passive immunityArtificially induced passive immunity—antibodies given after pathogen exposure

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18. vaccines  Benefits of vaccines  Spare the symptoms & discomfort of disease  Booster shots intensify immune response  Wiped out/lessened effects of some diseases  Problems of vaccines  Cellular memory poorly established  Can cause the disease the vaccine is trying to prevent

19. 14-4 Checkpoint 1.Distinguish between cell-mediated (cellular) immunity & antibody-mediated (humoral) immunity. 2.Identify the two forms of active immunity & the two types of passive immunity. 3.List the four general properties of adaptive immunity.

20. 14-6: Antibodies & Antigens Primary & Secondary Responses to Antigen Exposure  Primary response  Primary response—body’s initial response to antigen exposure  Takes time to develop (1 – 2 weeks)  Secondary response  Secondary response—exposure to same antigen triggers release of memory cells  Faster response than primary response 14 - 20

21. 14-6 Checkpoint 1.How does an antigen differ from an antibody? 2.Distinguish between the primary and secondary responses to an antigen.

22. 14-7: Abnormal Immune Responses Autoimmune Disorders  Autoimmune disorders  Autoimmune disorders—immune response mistakenly targets normal body cells & tissues  Rheumatoid arthritis (RA), type 1 diabetes Immunodeficiency Diseases  Immune system fails to develop or is blocked  AIDS

23. Allergies  Allergies  Allergies—inappropriate/excessive response to antigens allergens  Triggered by allergens  Immediate hypersensitivity  Immediate hypersensitivity—rapid & severe response to antigen  First exposure does not produce reaction  Second exposure causes inflammation response  Anaphylaxis hives  Anaphylaxis—allergen affects cells throughout body; causes swelling, hives  Severe cases can be fatal

24.  Cytotoxic reactions  Cytotoxic reactions occur following incompatible blood transfusion  Delayed hypersensitivities  Delayed hypersensitivities occur 2 – 3 days after exposure (poison ivy) antihistamines  Many signs & symptoms of hypersensitivities can be prevented with antihistamines

25. 14-7 Checkpoint 1.Under what circumstances is an autoimmune disorder produced? 2.In an immediate hypersensitivity, why isn’t there an allergic reaction after the first exposure to an antigen?