Lecture 11 the lymphatic system and immunity

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Lecture 11 the lymphatic system and immunity

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Lecture 11 the lymphatic system and immunity

  1. 1. Copyright 2010, John Wiley & Sons, Inc. Chapter 17 The Lymphatic System and Immunity
  2. 2. Copyright 2010, John Wiley & Sons, Inc. Immunity  Innate Immunity  Fast, non-specific and no memory  Barriers, pH extremes, Phagocytes & NK cells, fever, inflammation, complement, interferon  Adaptive Immunity  Slower, specific & has a memory  Lymphocytes: T-cells & B-cells
  3. 3. Copyright 2010, John Wiley & Sons, Inc. Lymphatic System  Lymphatic tissue  Reticular connective tissue containing lymphocytes  Bone marrow  Lymph- interstitial fluid in lymphatic vessels  Returns excess filtration from capillaries- to circulation  Transport dietary lipids  Maintenance & distribution- lymphoid organs  Filter bacteria and help active defenses
  4. 4. Copyright 2010, John Wiley & Sons, Inc. Lymphatic System
  5. 5. Copyright 2010, John Wiley & Sons, Inc. Lymphatic Vessels  Begin at lymphatic capillaries  Slightly larger than blood capillaries  Overlapping cells like one-way valve  Pressure will force fluid in  Merge to form larger & larger vessels  Thin walled and more valves than veins  Periodically have lymph nodes  Lymphocytes in capsuled structure   thoracic duct  L subclavian vein  At junction with jugular   R. lymphatic duct  R. subclavian vein
  6. 6. Copyright 2010, John Wiley & Sons, Inc. Lymphatic Vessels
  7. 7. Copyright 2010, John Wiley & Sons, Inc. Lymphatic Vessels
  8. 8. Copyright 2010, John Wiley & Sons, Inc. Lymphatic Flow  From tissue to veins  Pumped by muscle & respiratory pumps like venous return
  9. 9. Copyright 2010, John Wiley & Sons, Inc. Lymphatic Flow
  10. 10. Copyright 2010, John Wiley & Sons, Inc. Lymphatic Flow Interactions Animation  Lymph Formation and Flow You must be connected to the internet to run this animation.
  11. 11. Copyright 2010, John Wiley & Sons, Inc. Lymphatic Organs  Primary lymphatic organs- stem cells divide & develop into mature B & T-cells  Red bone marrow & thymus  Secondary organs: immune responses occur  Lymph nodes, spleen & lymphatic nodules
  12. 12. Copyright 2010, John Wiley & Sons, Inc. Thymus  Two lobed organ  Posterior to sternum, medial to lungs & superior to heart  T-cells divide & mature  Self reactive cells are removed
  13. 13. Copyright 2010, John Wiley & Sons, Inc. Lymph Nodes  Scattered throughout the body  Concentrated near mammary glands, axilla & groin  Contain mature B-cells, T-cells dendritic cells and macrophages  Filter lymph, trap foreign substances  Macrophages & lymphocytes destroy most foreign substances
  14. 14. Copyright 2010, John Wiley & Sons, Inc. Lymph Nodes
  15. 15. Copyright 2010, John Wiley & Sons, Inc. Spleen  Between stomach & diaphragm  Contains blood filled venous sinuses and RBCs, macrophages, lymphocytes plasma cells & granular leukocytes  destroys worn or defective blood cells & platelets  Stores platelets  attacks foreign substances in blood  Fetal hemopoiesis
  16. 16. Copyright 2010, John Wiley & Sons, Inc. Innate Immunity: Barriers  Skin: physical and chemical  Epidermal structure & constant shedding  Mucous membranes  Sticky mucus layer straps microbes, etc. and cilia move it out  Fluids: tears, saliva, perspiration, nasal secretions  Dilute and antibacterial action  Movement: flow of urine, defecation & vomiting
  17. 17. Copyright 2010, John Wiley & Sons, Inc. Internal Defenses: Proteins  Interferons  Interfere with viral reproduction in a cell  Complement System  Enhance other immune actions  Break cell membranes  Attract phagocytes  Tag microbial cells for destruction  Transferrins- bind iron and starve bacteria  Antimicrobial peptides: lyse microbes
  18. 18. Copyright 2010, John Wiley & Sons, Inc. Internal Defenses: Cells  Phagocytes specialized to ingest microbes and cellular debris  Neutrophils  Monocytes  macrophages  5-10% of lymphocytes = Natural Killer (NK) Cells  Destroy microbes & tumor cells  Present in lymph nodes & red bone marrow
  19. 19. Copyright 2010, John Wiley & Sons, Inc. Inflammation  Response to tissue damage  Indicated by redness, pain, heat & swelling
  20. 20. Copyright 2010, John Wiley & Sons, Inc. Inflammation 1. Damage  mast cells, basophils & platelets release histamine  increased permeability & vasodilation in blood vessels 2. Leakage of clotting proteins into tissue-  Isolate bacteria behind clot 3. Phagocytes attracted to site  Neutrophils & macrophages eat & die 4. Pocket of dead cells = pus  Moves to body surface or into cavity & is cleared
  21. 21. Copyright 2010, John Wiley & Sons, Inc. Inflammation
  22. 22. Copyright 2010, John Wiley & Sons, Inc. Fever  Abnormally high body temperature  New set-point of thermoregulation system  Normal temperature control action with new set point  Stimulated by many toxins or internal signals  Interleukin-1
  23. 23. Copyright 2010, John Wiley & Sons, Inc. Adaptive Immunity  Specifically directed against a particular type of invader  Involves cell or antibody directed against a particular antigen  Antigen can be any substance: microbe, food, pollen, tissue  Normally self–tolerant  Does not attack normal body tissue
  24. 24. Copyright 2010, John Wiley & Sons, Inc. Maturation of T and B cells  From stem cells in red bone marrow  B cells mature in bone marrow  T cells migrate to thymus  During maturation both make particular proteins in plasma membranes = antigen receptors
  25. 25. Copyright 2010, John Wiley & Sons, Inc. Types of Responses  Cell-mediated- T-cells attack directly  Killer T-cells  Antibody-mediated  B cells become plasma cells  Produce specific antibodies  Helper T cells aid both cell- and antibody- mediated responses
  26. 26. Copyright 2010, John Wiley & Sons, Inc. Antigens & Antibodies  Major Histocompatability Complex (MHC) = self antigens on cells surface  Unique to each individual  Allows T-cells to recognize foreign material  Antigen triggers plasma cell to produce antibodies  Y-shaped protein with variable antigen binding site on arms  Other end triggers recognition by phagocyte
  27. 27. Copyright 2010, John Wiley & Sons, Inc. Antigens & Antibodies
  28. 28. Copyright 2010, John Wiley & Sons, Inc. Antigens & Antibodies
  29. 29. Copyright 2010, John Wiley & Sons, Inc. Triggering Adaptive Response  Requires recognizing the foreign antigen  B-ceils can find it anywhere  T-cells need presentation with MHC  Antigen presenting cells (APC) do this  APCs macrophages, dendritic cells & B cells  In respiratory, GI, urinary, reproductive tracts & lymph nodes
  30. 30. Copyright 2010, John Wiley & Sons, Inc. Processing & Presenting Antigens  APC’s ingest & digest into fragments in vesicles  Synthesize MHC & pack in vesicles  Two vesicles fuse  Antigen fragments bind to MHC  Antigen-MHC complex inserted into plasma membrane  Presented to T-cells until a receptor matches & binds
  31. 31. Copyright 2010, John Wiley & Sons, Inc. Processing & Presenting Antigens
  32. 32. Copyright 2010, John Wiley & Sons, Inc. Cell Mediated Immunity  T-ceils also need costimulator  Interleukin-2 (IL-2)  Binding both  response  T-cell begins rapidly dividing  Forms a clone of many recognizing cells  Helper T cells  Release IL2, attract phagocytes, stimulate macrophages & B cells
  33. 33. Copyright 2010, John Wiley & Sons, Inc. Cell Mediated Immunity  Cytotoxic T cells – kill cells  Work against tumor cells transplanted cells & infected cells  Memory T cells- hang around for years, give rapid response
  34. 34. Copyright 2010, John Wiley & Sons, Inc. Cell Mediated Immunity
  35. 35. Copyright 2010, John Wiley & Sons, Inc. Cell Mediated Immunity
  36. 36. Copyright 2010, John Wiley & Sons, Inc. B-cells and Antibody-Mediated Response  Hang out in lymph nodes  Respond to antigen (faster if presented)  With IL-2 enlarge, divide and become a clone of plasma cells  Plasma cells produce & release antibodies that bind the antigen  Some remain as Memory B Cells  Ready to respond quickly if antigen met again
  37. 37. Copyright 2010, John Wiley & Sons, Inc. Secretion of Antibodies
  38. 38. Copyright 2010, John Wiley & Sons, Inc. Antibody Class Actions  Neutralizing antigen  Binds and neutralizes toxins  Immobilizing bacteria  Agglutinating  Connect pathogens to one another  easier phagocytosis  Activating complement  Enhancing phagocytosis  Binding attracts phagocytes
  39. 39. Copyright 2010, John Wiley & Sons, Inc. Immunological Memory  Long lasting antibodies & lymphocytes  Many sensitive memory cells   Much larger & quicker response next time = Secondary Response  Primary response can be naturally acquired  Or artificially acquired by vaccination  Killed cells, isolated antigens, parts of viruses
  40. 40. Copyright 2010, John Wiley & Sons, Inc. Immunological Memory Interactions Animation  Introduction to Disease Resistance You must be connected to the internet to run this animation.
  41. 41. Copyright 2010, John Wiley & Sons, Inc. Aging  Thymus atrophies  Fewer responsive T cells  Thus poorer B cell response  Poorer response to new infection
  42. 42. Copyright 2010, John Wiley & Sons, Inc. End of Chapter 17  Copyright 2010 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publishers assumes no responsibility for errors, omissions, or damages caused by the use of theses programs or from the use of the information herein.

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