Chapter 22:  The Lymphatic System Biology 142 AP R.L. Brashear-Kaulfers

Chapter 22: The Lymphatic System Biology 142 AP R.L. Brashear-Kaulfers PowerPoint PPT Presentation

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Pathogens. Microscopic organisms that cause disease:virusesbacteriafungiparasitesEach attacks in a specific way . The Lymphatic System Protects us against disease . Lymphocytes:Lymphatic system cells respond to:environmental pathogenstoxinsabnormal body cells, such as cancers . What is the difference between nonspecific and specific defense, and the role of lymphocytes in the immune response?.

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Chapter 22: The Lymphatic System Biology 142 AP R.L. Brashear-Kaulfers

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1. Chapter 22: The Lymphatic System Biology 142 A&P R.L. Brashear-Kaulfers

2. Pathogens Microscopic organisms that cause disease: viruses bacteria fungi parasites Each attacks in a specific way

3. The Lymphatic System Protects us against disease Lymphocytes: Lymphatic system cells respond to: environmental pathogens toxins abnormal body cells, such as cancers

4. What is the difference between nonspecific and specific defense, and the role of lymphocytes in the immune response?

5. Specific Defenses Lymphocytes: part of the immune response Identify, attack, and develop immunity to a specific pathogen Immunity- The ability to resist infection and disease

6. The Immune System All body cells and tissues involved in production of immunity: not just lymphatic system

7. Nonspecific Defenses Block or attack any potential infectious organism Cannot distinguish one attack from another

8. Organization of the Lymphatic System

9. 4 Parts of the Lymphatic System Lymph: a fluid similar to plasma does not have plasma proteins Lymphatic vessels (lymphatics): network that carries lymph from peripheral tissues to the venous system Lymphoid tissues and lymphoid organs: found throughout the body Lymphocytes, phagocytes, and other immune system cells

10. Function of the Lymphatic System To produce, maintain, and distribute lymphocytes- **Lymphocyte Production: - Lymphocytes are produced: in lymphoid tissues (e.g., tonsils) lymphoid organs (e.g., spleen, thymus) and in red bone marrow ** Lymphocytes Distribution: detect problems travel into site of injury or infection

11. Lymphocyte Circulation From blood to interstitial fluid (lymph) through capillaries Returns to venous blood through lymphatic vessels

12. The Circulation of Fluids From blood plasma to lymph and back to the venous system Also transports hormones, nutrients, and waste products

13. Lymphatic Vessels Are vessels that carry lymph Lymphatic system begins with smallest vessels: lymphatic capillaries (terminal lymphatics) Lymphatic Capillaries- Differ from blood capillaries in 4 ways: start as pockets rather than tubes have larger diameters have thinner walls flat or irregular in section

14. Lymphatic Capillaries

15. Lacteals Are special lymphatic capillaries in small intestine Transport lipids from digestive tract

16. Lymphatic Vessels and Valves

17. Lymph Flow From lymphatic capillaries to larger lymphatic vessels containing one-way valves Lymphatic vessels travel with veins

18. Lymphatic Ducts and the Venous System

19. The Lymphatic System Is divided into: 1) Superficial lymphatics - located in: skin mucus membranes serous membranes lining body 2) Deep lymphatics- Are larger vessels that accompany deep arteries and veins

20. Superficial and Deep Lymphatics Join to form large lymphatic trunks Trunks empty into 2 major collecting vessels: thoracic duct right lymphatic duct

21. The Inferior Thoracic Duct Collects lymph from: left bronchiomediastinal trunk left subclavian trunk left jugular trunk Empties into left subclavian vein The Right Lymphatic Duct Collects lymph from: right jugular trunk right subclavian trunk right bronchiomediastinal trunk Empties into right subclavian vein

22. Lymphedema Blockage of lymph drainage from a limb Causes severe swelling Interferes with immune system function

23. Why are lymphocytes important, and how are they distributed in the body? Lymphocytes Make up 20–30% of circulating leukocytes Most are stored, not circulating

24. 3 Classes of Circulating Lymphocytes T cells: thymus-dependent Make up 80% of circulating lymphocytes 2. B cells: bone–marrow derived Make up 10–15% of circulating lymphocytes Differentiate into plasma cells- Produce and secrete antibodies (immunoglobin proteins) 3. NK cells: natural killer cells

25. 3 Main Types of T Cells Cytotoxic T cells-Attack cells infected by viruses Produce cell-mediated immunity 2. Helper T cells- Stimulate function of T cells and B cells 3. Suppressor T cells-Inhibit function of T cells and B cells

26. Regulatory T Cells Are helper and suppressor T cells Control sensitivity of immune response Other T Cells Inflammatory T cells Suppressor and inducer T cells

27. Antigens Targets which identify any pathogen or foreign compound Immunoglobin Proteins (Ig’s) Also called antibodies (Ab) The binding of a specific antibody to its specific target antigen initiates antibody-mediated immunity: - A chain of events which destroys the target compound or organism

28. Natural Killer (NK) Cells Also called large granular lymphocytes Make up 5–10% of circulating lymphocytes Responsible for immunological surveillance Attack: foreign cells virus-infected cells cancer cells

29. Lymphocyte Distribution Tissues maintain different T cell and B cell populations Lymphocytes wander through tissues: enter blood vessels or lymphatics for transport can survive many years

30. Production and Distribution of Lymphocytes

31. Lymphopoiesis Lymphocyte production involves: bone marrow thymus peripheral lymphoid tissues Hemocytoblasts : In bone marrow, divide into 2 types of lymphoid stem cells

32. Lymphoid Stem Cells Group 1: remain in bone marrow produce B cells and natural killer cells Group 2: migrate to thymus produce T cells in environment isolated by blood-thymus barrier

33. T Cells and B Cells Migrate throughout the body: to defend peripheral tissues Retain their ability to divide: is essential to immune system function

34. Differentiation B cells differentiate: with exposure to hormone interleukin-7 T cells differentiate: with exposure to several thymic hormones Interleukin-7 - A cytokine produced by stromal cells in bone marrow

35. What are the structures and functions of lymphoid tissues and organs? Lymphoid Tissues : Connective tissues dominated by lymphocytes

36. Lymphoid Nodules

37. Lymphoid Nodule Areolar tissue with densely packed lymphocytes Germinal center contains dividing lymphocytes

38. Distribution of Lymphoid Nodules Lymph nodes Spleen Respiratory tract (tonsils) Along digestive and urinary tracts

39. Mucosa-Associated Lymphoid Tissue (MALT) Lymphoid tissues associated with the digestive system: aggregated lymphoid nodules: clustered deep to intestinal epithelial lining Appendix: mass of fused lymphoid nodules

40. The 5 Tonsils In wall of pharynx: left and right palatine tonsils pharyngeal tonsil (adenoid) 2 lingual tonsils

41. Lymphoid Organs Lymph nodes Thymus Spleen Are separated from surrounding tissues By a fibrous connective-tissue capsule

42. Lymph Nodes Range from 1–25 mm diameter

43. Afferent Lymphatic Vessels Carry lymph: from peripheral tissues to lymph node Efferent Lymphatic Vessels Leave lymph node at hilus Carry lymph to venous circulation

44. Lymph from Afferent Lymphatics Flows through lymph node in a network of sinuses: From subcapsular sinus: contains macrophages and dendritic cells Through outer cortex: contains B cells within germinal centers Through deep cortex: dominated by T cells Through the core (medulla): contains B cells and plasma cells organized into medullary cords Into hilus and efferent lymphatics

45. Lymph Node A filter: purifies lymph before return to venous circulation Removes: debris pathogens 99% of antigens

46. Antigen Presentation First step in immune response Extracted antigens are “presented” to lymphocytes: or attached to dendritic cells to stimulate lymphocytes

47. Lymphoid Functions Lymphoid tissues and lymph nodes: distributed to monitor peripheral infections respond before infections reach vital organs of trunk

48. Lymph Nodes of Gut, Trachea, Lungs, and Thoracic Duct Protect against pathogens in digestive and respiratory systems Lymph Glands Large lymph nodes at groin and base of neck Swell in response to inflammation

49. Lymphadenopathy Chronic or excessive enlargement of lymph nodes may indicate infections, endocrine disorders, or cancer

50. The Thymus

51. The Thymus Located in mediastinum Deteriorates after puberty: diminishing effectiveness of immune system Divisions of the Thymus Thymus is divided into 2 thymic lobes Septa divide lobes into smaller lobules

52. A Thymic Lobule Contains a dense outer cortex And a pale central medulla Thymus Hormones Thymosins Promote development of lymphocytes

53. Lymphocytes Divide in the cortex T cells migrate into medulla Mature T cells leave thymus by medullary blood vessels

54. Reticular Epithelial Cells in the Cortex Surround lymphocytes in cortex Maintain blood-thymus barrier Secrete thymic hormones that stimulate: stem cell divisions T cell differentiation

55. Reticular Epithelial Cells in the Medulla Form concentric layers (Hassall’s corpuscles) The medulla has no blood–thymus barrier: T cells can enter or leave bloodstream

56. The Spleen

57. 3 Functions of the Spleen Removal of abnormal blood cells and other blood components by phagocytosis Storage of iron recycled from red blood cells Initiation of immune responses by B cells and T cells: in response to antigens in circulating blood

58. Structure of the Spleen Attached to stomach by gastrosplenic ligament Contacts diaphragm and left kidney Splenic veins, arteries, and lymphatic vessels: communicate with spleen at hilus

59. Structure of the Spleen Inside fibrous capsule: Red pulp: contains many red blood cells Contains elements of circulating blood plus fixed & free macrophages White pulp: resembles lymphoid nodules

60. Trabecular Arteries Branch and radiate toward capsule Finer branches surrounded by white pulp Capillaries discharge red blood cells into red pulp

61. Splenic Circulation Blood passes through: network of reticular fibers Then enters large sinusoids (lined by macrophages): which empty into trabecular veins

62. Spleen Function Phagocytes and other lymphocytes in spleen: identify and attack damaged and infected cells in circulating blood

63. Body Defenses Provide resistance to fight infection, illness, and disease 2 categories of defenses: nonspecific defenses = Always work the same way , against any type of invading agent specific defenses = Protect against specific pathogens Depend on activities of lymphocytes Specific resistance (immunity): develops after exposure to environmental hazards

64. 7 Types of Nonspecific Resistance Physical barriers Phagocytic cells Immunological surveillance Interferons Complement Inflammation Fever

65. Nonspecific and Specific Defenses Operate together to provide resistance to infection and disease

66. The 7 Nonspecific Defenses

67. The 7 Nonspecific Defenses Physical Barriers -Keep hazardous materials outside the body Phagocytes -Attack and remove dangerous microorganisms Immunological Surveillance -Constantly monitors normal tissues: with natural killer cells (NK cells) Interferons -Trigger production of antiviral proteins in normal cells Antiviral proteins: do not kill viruses block replication in cell

68. The 7 Nonspecific Defenses Complement (C) Proteins -Form the complement system Complements action of antibodies Inflammation -Triggers a complex inflammatory response Fever -A high body temperature: increases body metabolism accelerates defenses inhibits some viruses and bacteria

69. What are the components and mechanisms of each nonspecific defense?

70. Physical Barriers Outer layer of skin Hair Epithelial layers of internal passageways Secretions that flush away materials: sweat glands, mucus, and urine Secretions that kill or inhibit microorganisms: enzymes, antibodies, and stomach acid

71. 2 Classes of Phagocytes Microphages: neutrophils and eosinophils Leave the bloodstream Enter peripheral tissues to fight infections Macrophages: large phagocytic cells derived from monocytes Distributed throughout body Make up monocyte–macrophage system (reticuloendothelial system)

72. Activated Macrophages Respond to pathogens in several ways: engulf pathogen and destroy it with lysosomal enzymes bind to pathogen so other cells can destroy it destroy pathogen by releasing toxic chemicals into interstitial fluid

73. 2 Types of Macrophages Fixed macrophages - also called histocytes: Microglia: found in central nervous system Kupffer cells: found in liver sinusoids Stay in specific tissues or organs: e.g., dermis and bone marrow Free macrophages -Travel through blood stream Special free macrophages: alveolar macrophages (phagocytic dust cells)

74. 3 Functional Characteristics of Free Macrophages and Microphages Move through capillary walls (emigration) Are attracted or repelled by chemicals in surrounding fluids (chemotaxis) Phagocytosis begins: when phagocyte attaches to target (adhesion) and surrounds it with a vesicle

75. Natural Killer Cell Function

76. NK Cell Function Identifies and attaches to abnormal cell (non-selective) Golgi apparatus in NK cell: forms perforin vesicles Vesicles release perforin (exocytosis) Perforin lyses abnormal cell membrane

77. NK Cells attack: cancer cells and cells infected with viruses 1) Cancer Cells -with tumor specific antigens: are identified as abnormal by NK cells some cancer cells avoid NK cells (immunological escape) 2) Viral Infections : Cells infected with viruses: present abnormal proteins on cell membranes allow NK cells to identify and destroy them

78. Interferons Proteins (cytokines) released by activated lymphocytes and macrophages- Cytokines - Chemical messengers released by tissue cells: to coordinate local activities to act as hormones to affect whole body

79. 3 Types of Interferons Alpha interferons: produced by leukocytes stimulate NK cells Beta interferons: secreted by fibroblasts slow inflammation Gamma interferons: secreted by T cells and NK cells stimulate macrophage activity

80. Complement Activation

81. Complement Activation Complements work together in cascades 2 pathways activate the complement system classical pathway alternative pathway

82. The Classical Pathway Fast method C1 binds to antibody molecule attached to antigen (bacterium) Bound protein acts as enzyme: catalyzes chain reaction

83. The Alternative Pathway Slow method Exposed to antigen: factor P (properdin) factor B and factor D interact in plasma ** Both pathways end with: conversion of inactive complement protein (C3) to active form (C3b)

84. 4 Effects of Complement Activation Stimulation of inflammation Attraction of phagocytes Enhancement of phagocytosis by opsonization: complements working with antibodies (opsonins) Destruction of target cell membranes: 5 complement proteins join to form membrane attack complex (MAC)

85. Inflammation Also called inflammatory response A localized response Triggered by any stimulus that kills cells or injures tissue

86. Cardinal Signs and Symptoms Swelling (tumor) Redness (rubor) Heat (calor) Pain (dolor)

87. 3 Effects of Inflammation Temporary repair and barrier against pathogens Retards spread of pathogens into surrounding areas Mobilization of local and systemic defenses: and facilitation of repairs (regeneration)

88. Inflammation and Tissue Repair

89. Inflammation and Tissue Repair Injured cells release: prostaglandins proteins potassium ions Changes interstitial environment and stimulates mast cells Mast cells release: histamine (increases capillary permeability) heparin (inhibits clotting

90. Inflammation and Tissue Repair Increased blood flow: raises local temperature causes area to swell, redden, and become painful Blood clot forms around damaged area, isolating it Complements: break down bacteria attract phagocytes

91. Inflammation and Tissue Repair Activated neutrophils attack debris and bacteria Phagocytes and foreign proteins: activate body’s specific defense system Macrophages clean up pathogens and cell debris Fibroblasts form scar tissue

92. Products of Inflammation Necrosis: local tissue destruction in area of injury Pus: mixture of debris and necrotic tissue Abscess: pus accumulated in an enclosed space

93. Fever - A maintained body temperature above 37°C (99°F) Pyrogens - Any material that causes the hypothalamus to raise body temperature: circulating pathogens, toxins, or antibody complexes Endogenous Pyrogens : Interleukin-1 (IL-1) pyrogen released by active macrophages a cytokine

94. Forms of Immunity

95. Specific Defenses Specific resistance (immunity): responds to specific antigens with coordinated action of T cells and B cells

96. T Cells Provide cell-mediated immunity Defends against abnormal cells and pathogens inside cells

97. B Cells Provide antibody-mediated immunity Defends against antigens and pathogens in body fluids

98. Forms of Immunity 1) Innate Immunity: present at birth 2) Acquired Immunity: after birth Active: antibodies develop after exposure to antigen Passive: antibodies are transferred from another source

99. Active Immunity Naturally acquired: through environmental exposure to pathogens Induced: through vaccines containing pathogens

100. Passive Immunity Naturally acquired: antibodies acquired from the mother Induced: by an injection of antibodies

101. 4 Properties of Immunity Specificity- Each T or B cell: responds only to a specific antigen, ignores all others Versatility-The body produces many types of lymphocytes: each fights a different type of antigen (Ag) active lymphocyte clones itself to fight specific Ag Memory-Some active lymphocytes (memory cells): stay in circulation provide immunity against new exposure Tolerance- Immune system ignores “normal” antigens

102. What are the differences between cell-mediated (cellular) immunity and antibody-mediated (humoral) immunity?

103. The Immune Response

104. The Immune Response 2 main divisions: cell mediated immunity (T cells) antibody mediated immunity (B cells)

105. What are the types of T cells and their functions in the immune response?

106. What are the types of T cells and their functions in the immune response? 1) Cytotoxic T Cells= also called Tc cells Attack cells infected by viruses Responsible for cell-mediated immunity 2) Helper T Cells= also called Th cells Stimulate function of T cells and B cells 3) Suppressor T Cells = also called Ts cells Inhibit function of T cells and B cells

107. Antigens and MHC Proteins

108. Antigen Recognition T cells only recognize antigens that are bound to glycoproteins in cell membranes

109. Antigen Presentation

110. MHC Proteins The membrane glycoproteins that bind to antigens Genetically coded in chromosome 6: the major histocompatibility complex (MHC) differs among individuals

111. 2 Classes of MHC Proteins Class I: found in membranes of all nucleated cells Pick up small peptides in cell and carry them to the surface: T cells ignore normal peptides abnormal peptides or viral proteins activate T cells to destroy cell Class II: found in membranes of antigen-presenting cells (APCs) found in lymphocytes Antigenic fragments: from antigenic processing of pathogens bind to Class II proteins inserted in cell membrane to stimulate T cells

112. Antigen-Presenting Cells (APCs) Responsible for activating T cells against foreign cells and proteins Phagocytic APCs : Free and fixed macrophages: in connective tissues Kupffer cells: of the liver Microglia: in the CNS

113. Pinocytic APCs Langerhans cells: in the skin Dendritic cells: in lymph nodes and spleen

114. What are the mechanisms of T cell activation and the differentiation of the major classes of T cells?

115. An Overview of the Immune Response

116. Antigen Recognition Inactive T cell receptors: recognize Class I or Class II MHC proteins recognize a specific antigen Binding occurs when MHC protein matches antigen

117. CD Markers Also called cluster of differentiation markers: in T cell membranes molecular mechanism of antigen recognition more than 70 types: designated by an identifying number CD3 Receptor Complex Found in all T cells

118. CD8 Markers Found on cytotoxic T cells and suppressor T cells Respond to antigens on Class I MHC proteins CD4 Markers Found on helper T cells Respond to antigens on Class II MHC proteins CD8 or CD4 Markers - Bind to CD3 receptor complex Prepare cell for activation

119. Costimulation For T cell to be activated, it must be costimulated: by binding to stimulating cell at second site which confirms the first signal

120. 2 Classes of CD8 T Cells Activated by exposure to antigens on MHC proteins: one responds quickly: producing cytotoxic T cells and memory T cells the other responds slowly: producing suppressor T cells

121. Activation of Cytotoxic T Cells

122. Actions of Cytotoxic T Cells Release perforin: to destroy antigenic cell membrane Secrete poisonous lymphotoxin: to destroy target cell Activate genes in target cell: that cause cell to die

123. Slow Response Can take up to 2 days from time of first exposure to an antigen, for cytotoxic T cells to reach effective levels

124. Memory Tc Cells Produced with cytotoxic T cells Stay in circulation Immediately form cytotoxic T cells: if same antigen appears again

125. Suppressor T Cells Secrete suppression factors Inhibit responses of T and B cells After initial immune response Limit immune reaction to single stimulus

126. Activation of Helper T Cells

127. 4 Functions of Cytokines Stimulate T cell divisions: produce memory T cells accelerate cytotoxic T cell maturation Attract and stimulate macrophages Attract and stimulate NK cells Promote activation of B cells

128. Pathways of T Cell Activation

129. KEY CONCEPT Cell-mediated immunity involves close physical contact between activated Tc cells and foreign, abnormal or infected cells T cell activation usually involves: antigen presentation by phagocytic cell costimulation by cytokines from active phagocytes Tc cells may destroy target cells through local release of cytokines, lymphotoxins, or perforin

130. What are the mechanisms of B cell activation and the differentiation of plasma cells and memory B cells?

131. B Cells Responsible for antibody-mediated immunity Attack antigens by producing specific antibodies Millions of populations, each with different antibody molecules

132. B Cell Sensitization Corresponding antigens in interstitial fluids bind to B cell receptors B cell prepares for activation Preparation process is sensitization

133. B Cell Sensitization and Activation

134. Helper T Cells Sensitized B cell is prepared for activation, but needs helper T cell activated by same antigen B Cell Activation Helper T cell binds to MHC complex: secretes cytokines that promote B cell activation and division

135. B Cell Division Activated B cell divides into: plasma cells -Synthesize and secrete antibodies into interstitial fluid Memory B cells- Like memory T cells remain in reserve to respond to next infection

136. Antibody Structure

137. Antibody Structure 2 parallel pairs of polypeptide chains: 1 pair of heavy chains 1 pair of light chains Each chain contains: constant segments variable segments-Determine specificity of antibody molecule

138. 5 Heavy-Chain Constant Segments Determine 5 types of antibodies: IgG IgE IgD IgM IgA

139. Binding Sites Free tips of 2 variable segments: form antigen binding sites of antibody molecule which bind to antigenic determinant sites of antigen molecule

140. Antibody Function

141. A Complete Antigen Has 2 antigenic determinant sites Binds to both of antigen binding sites of variable segments of antibody Exposure to a complete antigen leads to: B cell sensitization immune response

142. A Hapten Also called partial antigen Must attach to a carrier molecule to act as a complete antigen Dangers of Haptens Antibodies produced attack both hapten and carrier molecule If carrier is “normal”: antibody attacks normal cells e.g., penicillin allergy

143. 5 Classes of Antibodies

144. 5 Classes of Antibodies Also called immunoglobins (Igs) Are found in body fluids Are determined by constant segments Have no effect on antibody specificity

145. 7 Functions of Antigen–Antibody Complexes Neutralization of antigen binding sites Precipitation and agglutination: formation of immune complex Activation of complement Attraction of phagocytes Opsonization: increasing phagocyte efficiency Stimulation of inflammation Prevention of bacterial and viral adhesion

146. KEY CONCEPT Antibody-mediated immunity involves the production of specific antibodies by plasma cells derived from activated B cells B cell activation usually involves: antigen recognition, through binding to surface antibodies, costimulation by a Th cell Antibodies produced by active plasma cells bind to target antigen and: inhibit its activity or destroy it remove it from solution promote its phagocytosis by other defense cells

147. Primary and Secondary Responses Occur in both cell-mediated and antibody-mediated immunity

148. Primary and Secondary Responses to Antigen Exposure First exposure: produces initial response (Primary) Next exposure: triggers secondary response more extensive and prolonged memory cells already primed

149. The Primary Response Takes time to develop Antigens activate B cells Plasma cells differentiate Antibody titer slowly rises Peak response: can take 2 weeks to develop declines rapidly IgM: is produced faster than IgG is less effective

150. The Secondary Response Activates memory B cells: at lower antigen concentrations than original B cells secrete antibodies in massive qualities Effects of Memory B Cell Activation IgG: rises very high and very quickly can remain elevated for extended time IgM: production is also quicker slightly extended

151. KEY CONCEPT Immunization produces a primary response to a specific antigen under controlled conditions If the same antigen appears at a later date, it triggers a powerful secondary response that is usually sufficient to prevent infection and disease

152. Summary of the Immune Response Specific and nonspecific defenses

153. Body Responses to Bacterial Infection

154. Combined Immune System Responses

155. Combined Responses to Bacterial Infection Neutrophils and NK cells begin killing bacteria Cytokines draw phagocytes to area Antigen presentation activates: helper T cells cytotoxic T cells B cells activate and differentiate Plasma cells increase antibody levels

156. Combined Responses to Viral Infection Similar to bacterial infection But cytotoxic T cells and NK cells are activated by contact with virus-infected cells

157. Summary: Cells of the Immune System

158. KEY CONCEPT Viruses replicate inside cells, whereas bacteria may live independently Antibodies (and administered antibiotics) work outside cells, so are primarily effective against bacteria rather than viruses Antibiotics cannot fight the common cold or flu T cells, NK cells, and interferons are the primary defense against viral infection

159. What is the origin, development, activation, and regulation of normal resistance to disease?

160. Immune System Development Fetus can produce immune response or immunological competence: after exposure to antigen at about 3–4 months

161. Development of Immunological Competence Fetal thymus cells migrate to tissues that form T cells Liver and bone marrow produce B cells 4-month fetus produces IgM antibodies

162. Before Birth Maternal IgG antibodies: pass through placenta provide passive immunity to fetus After Birth Mother’s milk provides IgA antibodies: while passive immunity is lost

163. Normal Resistance Infant produces IgG antibodies through exposure to antigens Antibody, B-cell, and T-cell levels slowly rise to adult levels: about age 12

164. Hormones of the Immune System

165. 6 Groups of Hormonal Cytokines Interleukins Interferons Tumor necrosis factors Chemicals that regulate phagocytic activities Colony stimulating factors Miscellaneous cytokines

166. What are the origins of autoimmune disorders, immunodeficiency diseases, and allergies, and what are some examples of each?

167. Immune Disorders Autoimmune disorders- A malfunction of system that recognizes and ignores “normal” antigens Activated B cells make autoantibodies against body cells Immunodeficiency disease- Thyroiditis Rheumatoid arthritis Insulin-dependent diabetes mellitus Allergies -

168. Immunodeficiency Diseases Problems with embryological development of lymphoid tissues: can result in severe combined immunodeficiency disease (SCID) Viral infections such as HIV: can result in AIDS Immunosuppressive drugs or radiation treatments: can lead to complete immunological failure

169. Allergies Inappropriate or excessive immune responses to antigens Allergens: antigens that trigger allergic reactions

170. 4 Categories of Allergic Reactions Type I: immediate hypersensitivity Type II: cytotoxic reactions Type III: immune complex disorders Type IV: delayed hypersensitivity

171. Type I Allergy (1) Also called immediate hypersensitivity A rapid and severe response to the presence of an antigen Most commonly recognized type of allergy Includes allergic rhinitis (environmental allergies) Sensitization leads to: production of large quantities of IgE antibodies distributed throughout the body Second exposure leads to: massive inflammation of affected tissues

172. Type I Allergy (2) Severity of reaction depends on: individual sensitivity locations involved Allergens in blood stream may cause anaphylaxis

173. Anaphylaxis Can be fatal Affects cells throughout body Changes capillary permeability: produce swelling (hives) on skin Smooth muscles of respiratory system contract: make breathing difficult Peripheral vasodilatation: can cause circulatory collapse (anaphylactic shock)

174. Antihistamine Drugs Block histamine released by MAST cells Can relive mild symptoms of immediate hypersensitivity

175. Stress and the Immune Response Glucocorticoids: secreted to limit immune response long-term secretion (chronic stress): inhibits immune response lowers resistance to disease

176. Functions of Glucocorticoids Depression of the inflammatory response Reduction in abundance and activity of phagocytes Inhibition of interleukin secretion

177. Aging and the Immune Response Immune system deteriorates with age, increasing vulnerability to infections and cancer

178. 4 Effects of Aging on Immune Response Thymic hormone production: greatly reduced T cells: become less responsive to antigens Fewer T cells reduce responsiveness of B cells Immune surveillance against tumor cells declines

179. Integration with Other Systems

180. Disorders of the Lymphatic System 3 categories affect immune response: disorders resulting from: an insufficient immune response an inappropriate immune response an excessive immune response

181. SUMMARY (1) Divisions of the lymphatic system: lymphatic vessels (lymphatics) lymph lymphoid tissues and organs Types of lymphocytes: T cells B cells NK cells Lymphoid tissues and organs: Nodules nodes MALT thymus spleen

182. SUMMARY (2) 7 nonspecific defenses: physical barriers phagocytes immunological surveillance interferons complement inflammation fever

183. SUMMARY (3) Specific defenses: cell-mediated immunity antibody mediated immunity Forms of immunity: innate or acquired active or passive Properties of immunity: specificity, versatility, memory, andtolerance

184. SUMMARY (4) T cells and cell-mediated immunity: antigen presentation MHCs and APCs antigen recognition CD8 T cell activation CD4 T cell activation

185. SUMMARY (5) B cells and antibody-mediated immunity: sensitization plasma cells and memory B cells antibody structure antigen–antibody complex 5 classes of immunoglobins

186. SUMMARY (6) Primary and secondary responses to antigen exposure Hormones and the immune system: interleukins, interferons, TNFs, and CSFs Immune disorders Effects of aging on the immune response

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