Chapter 20 Lymphatic System

  1. Content in the Lymphatic System
    • lymph nodes
    • diffuse lymphatic tissue and nodules
    • lymphatic vessels
    • spleen
    • thymus
  2. Functions of the Lymphatic System
    • filter dead material and infectious organisms from lymph fluid
    • house germinating centers for lymphocytes
    • vessels absorb fats from GI tract and return to the blood
    • vessels return fluids in tissues not reabsorbed by capillaries to blood
  3. Structure of Lymphatic Vessels
    • valves, thin walled and compliant
    • start as tiny dead end vessels
    • not tightly packed cell
    • design of the system is not symmetrical; right side just shoulder and arm; left side does all the rest of body
  4. Lymph nodes
    • have cortex and medulla
    • -cortex contains germinating centers
    • -medulla has reticular fibers for trapping and filtering items form lymph
    • -WBC's hang out on fibers and phagocytize bacteria etc.
  5. Location of Nodes
    axillary, cervical, and inguinal etc.
  6. Spleen structure
    like a giant lymph node but functions are different (gets rid of old RBCs)
  7. Functions of the Spleen
    • filters blood with reticular fibers
    • connected to blood system
    • stores about 1 liter of blood
    • removes old RBC's from blood
    • germinating centers for lymphocytes
  8. What is the thymus and where is it located?
    • top of the heart
    • it makes chemical/ hormones that stimulate WBC
  9. How does the lymphatic fluid return to the blood stream?
    it goes to the subclavious vein and that dumps it in veins which return it to the heart
  10. Types of leukocytes
    granular and agranular
  11. Types of granular leukocytes
    • neutrophils
    • basophils
    • eosinophils
  12. Types of agranular leukocytes
    • monocytes
    • lymphocytes
  13. Neutrophil
    • polymorphonucleated cells (PMN) (nucleus can take many shapes)
    • phagocytosis (engolfs things)
    • NSIS (non specific immune system)
  14. Basophil
    • circulates in blood
    • (closely related cell found in tissues; mast cell)
    • allergic reactions
    • Part of SIS (specific immune system)
  15. Eosinophil
    • initate and suppress allergic reactions
    • fight parasites and tapeworms
    • part to SIS
    • negitive feedback for basophils
  16. monocytes
    • circulation precursors to marcophages
    • take on many roles and specific names
    • phagocytic cells
    • function mainly with SIS
    • they become antigen presenting cells (APC)
  17. lymphocytes
    • B: make antibodies; part of AMI (antibody mediated immunity)
    • T: fight infections through other means; part of CMI (cell mediated immunity)
  18. Natural killer cells
    find cancer cells and virus infected cells on their own
  19. Non-specific resistance definition:
    • innate mechanisms that all members of your species will have
    • mechanism can not be enhanced with repeated exposure
    • they system reacts the same to each infection; not specific response
    • theres no memory component
  20. Non-specific resistance mechanisms of resistance:
    • healthy skin
    • mucous membrane
    • tears, stomach acids, oils in skin
    • phagocytic WBC's
    • -create compoundsthat are cytolytic to pathogens as well as to surrounding tissue
    • natural killer cells
    • interferon
    • complement system
    • fever response
    • inflammatory response
  21. Natural killer cells (NK)
    • locate and destroy 'enemy' cells
    • -dont need the help of other WBC's to find target and destroy it
    • -first line of defense against cancer cells
  22. Interferon
    • anti-viral warning compound; one of the cytokines
    • -made by dying cells as a warning to healthy cells
    • -uses that second messenger system
    • -stimulates uninfected cells to make AVP (anti-viral proteins)
    • -Can also activate NK cells
  23. Complement system
    • set of plasma proteins made in liver
    • activation or complement fixations leads to a series of enzymatic responses; cascade response
  24. Alternative Complement pathway
    • complement protein C3 'spontaneously' splits due to the presense of certain ingredients in pathogentic, infected, & malignant cells
    • or the plasma protein lectin blinds to bacterial components and casues C3 to split
  25. Antigen- antibody union
    • classical pathway
    • specific immunity
    • leads to C3 activation
  26. Functions of the Complement system
    • cytolysis of infectious organism (due to membrane attack complex)
    • act as 'glue' for macrophages and the infectious target immunoadherence or opsonization
    • causes enhancement of inflammatory response
    • Clears Ag-Ab complexes by sticking them on RBC's and allowing macrophages to find and destroy the complexes as they pass through the liver or the spleen
  27. fever response
    • release endogenous pyrogens
    • alters action of the hypothalamus
    • depress bacterial reproductions and viral replication
    • promotes healing through increased metabolism
  28. inflammatory response
    • redness, pain, swelling, and increased temp
    • stop infection form spreading; bring in WBC's
    • vasodilation allows things in blood to enter area
  29. Antigens
    • anything "not of self"; foreign particles
    • something's are highly immunogenic or antigenic
    • -more elaborate compounds will have more antigenic regions
    • antigenic determinants
    • hapten: too small for system to 'see'
  30. Active acquired (specific) immunity
    • active natural: get sick; survive; make Ab and become immune
    • active artifical: get vaccine; make Ab's; ready if ever exposed
  31. Passive acquired immunity
    • passive natural: mother to fetus
    • passive artificial: borrow antibodies for short term immunity; can't wait for your own system to take the time to respond
  32. Antibodies:
    proteins made specifically to bind to a specific antigen; lock and key mechanism
  33. Structure of antibodies
    • constant region
    • variable region
    • Fc region: very end of the constant sem region
  34. Function of Ab's
    • trap: agglutinate and precipitate the Ag's
    • neutralization
    • activate complement
  35. IgG
    • make up ~ 80% of the serum antibodies
    • half-life of 7-23 days
    • a monomer
    • activate the classical complement pathway
    • Fc portion can bind to macrophages and neutrophils
    • is able to cross the placenta
  36. IgM
    • make up ~ 10% of the serum anitbodies
    • the first antibody produced during an immune response
    • half-life of 5 days
    • pentamer
    • activate the classical complement pathways
  37. IgA
    • make up~ 6% of the serum anitbodies
    • half-life ~5 days
    • found mainly in body secretion as secretory IgA where it protects interal body surfaces exposed to teh environment by blocking the attachment fo bacteria and viruses to mucous membrane
    • provides passive immunity to baby in mother's milk
    • made primarily in the mucosal- associated lymphoid tissue
    • appears mostly as a dimer 2 "Y" shaped tissues
    • secretory component to protect it from digestive enzymes in the secretion
    • fc protion of secretory IgA binds to component of mucous
  38. IgE
    • makes up ~0.002% of the serum antibodies w/ a half-life of 2 days
    • tightly bond to basophils and mast cells via its Fc region
    • monomer
    • response to parasitic worms; ofter made in response to allergen
    • protect external mucosal surgaces by promoting inflam, enabling IgG, complement proteins, and leucocytes to enter the tissues
    • Fc portion of IgE can bind to mast cells and basophils where it mediates amny allergic reactions
  39. Major histocompatibilty Complex- I (MHC)
    • found in all nucleated cells
    • hold onto components that signal damaged or diseased
    • cancer cells or virus infected cells can be noticed and destroyed w/ this method
    • send a 'kill me' signal to other cells
  40. Major histocompatibilty complex- II (MHC)
    • these are HLA's
    • will hold onto the antigenic 'pieces' of engulfed organisms
  41. Ab production
    • A. young B cell has prototype of Ab's on surface; find and internalizes the anitgen
    • B. tell cell line must be found by an APC
    • 1.Helper T cells (and maybe) APC find B cells and cause B cells to proliferate
    • C.Cells use MCH II to recognize each other
    • D. release of chemical signals from activated T cell cause repsonses in B cells
    • E.B cell divides making plasma cells, and memory B cells for use later
    • F. massive amounts of Ab's produced per second
    • G. finding righ B cell/stimulation can take 5 days to 2 weeks
    • H. next exposure will cause even greater amounts of Ab's to be made at a faster rate
  42. Cell mediated immunity (CMI)
    • A.Involves T cells and not Ab production
    • including helper T cells, cytotoxic T cells, memory T cells, and regulatory T cells
  43. Helper T cells
    stimulate T and B cell mitosis and activation (thus leads to increase Ab production)
  44. cytotoxic T cells
    • use enzymes like perforin
    • also make an interleukin which acts as a migration inhibiting factor for macrophages
    • TNF: tumor necrosis factor
  45. memory T cells
    • watchdogs; wait until next exposure and initiate the T cells recall response
    • send out chemotactic signal for variety of cells
    • will proliferate into various kinds of T cells
  46. regulatory T cells
    • slow down response
    • causing a little bit of negitive feedback
  47. Type I hypersensitivity
    • allergies
    • Sx: localized vs. systemic
    • response involved IgE, mast cells and eosinophils
    • details of degranulation:
    • mast cell or basophil releases histamine and other compounds that lead to sx such as: vasodilation, increase mucous membrane production, bronchial tube constriction inflammatory responses, eosinophils release anit- histamines
  48. What factors will determine the degree of a Type I reaction?
    amount of IgE, # of mast cells vs. # of eosinophils, IgG levels, where Ag enters the body, how much Ag enters
  49. Treatment of Type I
    anti- histamines, immunosuppressants, may need epinephrine in systemic reactions, try to raise IgG levels as blocker antibody, take anti- leukotryenes
  50. Type II
    • cellular antigen source is destroyed; cytotoxic
    • 1.complement fixation by IgG or IgM leads to cell lysis
    • ex: transfusion reaction, transplant rejection, erythroblastosis fetalis
  51. Type III
    • immune complex disorder
    • 1.Make Ab's against own tissues; systems ability to recongize self is flawed
    • 2. large #s of Ab's lead to inflammatory responses in tissue and compliment fixation
    • 3. Ex: RA, lupus
  52. Type IV: Delayed hypersensitivity
    • takes one to two days fro sx
    • sx are more prolonged
    • damage is due to too many macrophages being called to the are (self- destruction results)
    • contract dermatitis: poison ivy
    • IDD: destruction of beta cells by cytotoxic T cells
  53. ALL DONE!!!
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Chapter 20 Lymphatic System
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