lymphatic system and body defenses
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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. SECTION 22-3 Nonspecific Defenses. Nonspecific Defenses, Physical barriers. - PowerPoint PPT PresentationTRANSCRIPT
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• 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
Lymphatic system and body defenses
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SECTION 22-3 Nonspecific Defenses
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• Keep hazardous organisms outside the body
• Includes hair, epithelia, secretions of integumentary and digestive systems
Nonspecific Defenses, Physical barriers
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Figure 22.10 Nonspecific Defenses (Part 1 - Physical Barriers)
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• 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
Nonspecific Defenses, Phagocytes
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Figure 22.10 Nonspecific Defenses(Part 2 - Phagocytes)
Figure 22.10
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• Constant monitoring of normal tissue by NK cells
• NK cells
• Recognize cell surface markers on foreign cells
• Destroy cells with foreign antigens
Nonspecific Defenses, Immunological surveillance
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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
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Figure 22.10 Nonspecific Defenses(Part 3 - Immunological Surveillance)
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Figure 22.11 How Natural Killer Cells Kill Cellular Targets
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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
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Figure 22.10 Nonspecific Defenses(Part 4 - Interferons)
Figure 22.10
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Nonspecific Defenses, Complement system
• Cascade of ~11 plasma complement proteins (C)
• Destroy target cell membranes
• Stimulate inflammation
• Attract phagocytes
• Enhance phagocytosis
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Complement proteins interact with on another via two pathways
• Classical
• Alternative
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Figure 22.10 Nonspecific Defenses(Part 5 - Complement System)
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Figure 22.12 Complement Activation
Figure 22.12
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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
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Figure 22.10 Nonspecific Defenses(Part 6 - Inflammatory Response)
Figure 22.10
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Figure 22.13 Inflammation
Figure 22.13
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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
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Figure 22.10 Nonspecific Defenses(Part 7 - Fever)
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SECTION 22-4 Specific Defenses
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Forms of immunity
• Innate immunity
• Genetically determined
• Present at birth
• Acquired immunity
• Not present at birth
• Achieved by exposure to antigen
• Active immunity
• Passive immunity
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Figure 22.14 Types of Immunity
Figure 22.14
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Properties of immunity
• Specificity – activated by and responds to a specific antigen
• Versatility – is ready to confront any antigen at any time
• Memory – “remembers” any antigen it has encountered
• Tolerance – responds to foreign substances but ignores normal tissues
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The immune system response
• Antigen triggers an immune response
• Activates T cells and B cells
• T cells are activated after phagocytes exposed to antigen
• T cells attack the antigen and stimulate B cells
• Activated B cells mature and produce antibody
• Antibody attacks antigen
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Figure 22.15 An Overview of the Immune Response
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SECTION 22-5 T cells and Cell-mediated Immunity
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Major types of T cells
• Cytotoxic T cells (TC) – attack foreign cells
• Helper T cells (TH) – activate other T cells and B cells
• Suppressor T cells (TS) – inhibit the activation of T and B cells
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Antigen presentation
• Antigen-glycoprotein combination appears on a cell membrane
• Called MHC proteins (Major Histocompatibility Complex)
• Coded for by genes of the MHC
• T-cells sensitive to the antigen are activated upon contact
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MHC classes
• Class I – found on all nucleated cells
• Class II – found on antigen presenting cells and lymphocytes
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Lymphocytes respond to antigens bound to either class I or class II MHC proteins
• Antigen recognition
• T cell membranes contain CD markers
• CD3 markers present on all T cells
• CD8 markers on cytotoxic and suppressor T cells
• CD4 markers on helper T cells
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Figure 22.16 Antigens and MHC Proteins
Figure 22.16
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Figure 22.16 Antigens and MHC Proteins
Figure 22.16a
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Figure 22.16 Antigens and MHC Proteins
Figure 22.16b
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Activation of CD8 cells
• Responds quickly giving rise to other T cells
• Cytotoxic T cells – seek out and destroy abnormal cells• lymphotoxin
• Memory TC cells – function during a second exposure to antigen
• Suppressor T cells – suppress the immune response
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Figure 22.17 Antigen Recognition and the Activation of Cytotoxic T Cells
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Figure 22.17 Antigen Recognition and the Activation of Cytotoxic T Cells
Animation: Cytotoxic T Cell ActivationPLAY
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Activation of CD4 T cells by antigens presented on class II MHC proteins
• Produces helper T cells and memory T cells
• Activated helper T cells
• Secrete lymphokines that coordinate specific and nonspecific defenses
• Enhance nonspecific defenses
• Stimulate the activity of NK cells
• Promote activation of B cells
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Figure 22.18 Antigen Recognition and Activation of Helper T cells
Animation: Antigen Recognition and Helper T Cell ActivationPLAY
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Figure 22.19 A Summary of the Pathways of T Cell Activation
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Fundamentals of
Anatomy & PhysiologySIXTH EDITION
Frederic H
. Martini
PowerPoint® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii
Chapter 22, part 4
The Lymphatic System and Immunity
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SECTION 22-6 B Cells and Antibody-mediated Immunity
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B cell sensitization of activation
• Sensitization – the binding of antigens to the B cell membrane antibodies
• Antigens then displayed on B cell Class II MHC
• TH cells activated by same antigen stimulate B cell
• Active B cell differentiates into Memory B Cell or Plasma cell
• Plasma cells synthesize and release antibody
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Figure 22.20 The Sensitization and Activation of B Cells
Animation: B Cells and Antibody ProductionPLAY
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Antibodies structure
• Antibodies are Y-shaped proteins consisting of:
• Two parallel polypeptide chains
• Heavy chains and light chains
• Constant region and variable region
• Antigen binding site
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Figure 22.21 Antibody Structure
Figure 22.21
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Figure 22.21 Antibody Structure
Figure 22.21a
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Figure 22.21 Antibody Structure
Figure 22.21b-d
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Actions of antibodies include:
• Neutralization
• Agglutination and precipitation
• Activation of complement
• Attraction of phagocytes
• Opsinization
• Stimulation of inflammation
• Prevention of adhesion
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Classes of Antibodies (immunoglobins)
• IgG – resistance against many viruses, bacteria and bacterial toxins
• IgE – accelerates local inflammation
• IgD – found on the surface of B cells
• IgM – first type secreted after antigen arrives
• IgA – primarily found in glandular sec
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Primary and secondary antibody response
• Primary response
• Takes about two weeks to develop
• Produced by plasma cells
• Secondary response
• Rapid increase in IgG
• Maximum antibody titer app
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Figure 22.22 The Primary and Secondary Immune Responses
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Figure 22.23 An Integrated Summary of the Immune Response
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Figure 22.25 The Course of the Body’s Response to Bacterial Infection
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SECTION 22-7 Normal and Abnormal Resistance
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Development of the Immune Response
• Immunological competence
• The ability to demonstrate an immune response after exposure to an antigen
• Fetuses receive immunity from the maternal bloodstream
• Infants acquire immunity following exposure
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Immune disorders
• Autoimmune disorders
• Immune response mistakenly targets normal cells
• Immunodeficiency diseases
• Immune system does not develop properly or is blocked
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Allergies
• Inappropriate or excessive immune response to allergens
• Anaphylaxis
• Circulating allergen affects mast cells throughout body
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Figure 22.26 The Mechanism of Anaphylaxis
Figure 22.26
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Stress and the immune response
• Interleukin-1 released by active macrophages
• Triggers release of ACTH resulting in glucocorticoid release
• Moderates the immune response
• Lowers resistance to disease
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Stress can cause the following:
• Depression of the inflammatory response
• Phagocytic reduction
• Inhibition of interleukin secretion
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• The structure and function of lymphatic cells, tissues and organs
• The body’s nonspecific defenses and the components and mechanisms of each
• Specific resistance, cell-mediated immunity and antibody mediated immunity
• The role of the T cell, B cell and antibodies in specific immunity
You should now be familiar with: