1 / 26

Chapter 22, part 2

Chapter 22, part 2. The Lymphatic System and Immunity. The Thymus. Located behind sternum in anterior mediastinum Capsule Two lobes Divided into lobules, each with a cortex and medulla Cortical lymphocytes surrounded by reticular endothelial cells Maintain blood–thymus barrier

Download Presentation

Chapter 22, part 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 22, part 2 The Lymphatic System and Immunity

  2. The Thymus • Located behind sternum in anterior mediastinum • Capsule • Two lobes • Divided into lobules, each with a cortex and medulla • Cortical lymphocytes surrounded by reticular endothelial cells • Maintain blood–thymus barrier • Secretes thymic hormones: thymosins, thymopoietins, and thymulin

  3. Figure 22.8 The Thymus Figure 22.8a-c

  4. The Spleen • Largest mass of lymphoid tissue • Cellular components form pulp • Red pulp contains RBC • White pulp similar to lymphoid nodules • Spleen functions include • Removal of abnormal blood cells and other blood components • Storage of iron • Initiation of the specific immune response

  5. Figure 22.9 The Spleen Figure 22.9a-c

  6. Lymphatic system and body defenses • Nonspecific defenses • Do not distinguish one type of threat from another • 7 types • Specific defenses • Protect against particular threats • Depend upon the activation of lymphocytes

  7. SECTION 22-3Nonspecific Defenses

  8. Nonspecific Defenses, Physical barriers • Keep hazardous organisms outside the body • Includes hair, epithelia, secretions of integumentary and digestive systems

  9. Figure 22.10 Nonspecific Defenses (Part 1 - Physical Barriers) Figure 22.10

  10. Nonspecific Defenses, Phagocytes • Remove cellular debris and respond to invasion by foreign pathogens • Monocyte-macrophage system - Fixed and free • Microphages – Neutrophils and eosinophils • Move by diapedesis • Exhibit chemotaxis

  11. Figure 22.10 Nonspecific Defenses(Part 2 - Phagocytes) Figure 22.10

  12. Nonspecific Defenses, Immunological surveillance • Constant monitoring of normal tissue by NK cells • NK cells • Recognize cell surface markers on foreign cells • Destroy cells with foreign antigens

  13. NK cell activation • Recognition of unusual surface proteins • Rotation of the Golgi toward the target cell and production of perforins • Release of perforins by exocytosis • Interaction of perforins causing cell lysis

  14. Figure 22.10 Nonspecific Defenses(Part 3 - Immunological Surveillance) Figure 22.10

  15. Figure 22.11 How Natural Killer Cells Kill Cellular Targets Figure 22.11

  16. Nonspecific Defenses, Interferons (cytokines) • Small proteins released by virally infected cells • Trigger the production of antiviral proteins • Three major types of interferons are: • Alpha– produced by leukocytes and attract/stimulate NK cells • Beta– secreted by fibroblasts causing slow inflammation • Gamma – secreted by T cells and NK cells stimulate macrophage activity

  17. Figure 22.10 Nonspecific Defenses(Part 4 - Interferons) Figure 22.10

  18. Nonspecific Defenses, Complement system • Cascade of ~11 plasma complement proteins (C) • Destroy target cell membranes • Stimulate inflammation • Attract phagocytes • Enhance phagocytosis

  19. Complement proteins interact with on another via two pathways • Classical • Alternative

  20. Figure 22.10 Nonspecific Defenses(Part 5 - Complement System) Figure 22.10

  21. Figure 22.12 Complement Activation Figure 22.12

  22. Nonspecific Defenses, Inflammation • Localized tissue response to injury producing • Swelling • Redness • Heat • Pain • Effects of inflammation include • Temporary repair of injury • Slowing the spread of pathogens • Mobilization of local, regional, and systemic defenses

  23. Figure 22.10 Nonspecific Defenses(Part 6 - Inflammatory Response) Figure 22.10

  24. Figure 22.13 Inflammation Figure 22.13

  25. Nonspecific Defenses, Fever • Maintenance of a body temperature above 37.2oC (99oF) • Pyrogens reset the hypothalamic thermostat and raise body temperature • Pathogens, toxins, antigen-antibody complexes can act as pyrogens

  26. Figure 22.10 Nonspecific Defenses(Part 7 - Fever) Figure 22.10

More Related