GSU BIOL 2240 - Immunity (30 pages)

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Immunity



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Immunity

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Pages:
30
School:
Georgia State University
Course:
Biol 2240 - Intro to Human Physiology
Intro to Human Physiology Documents
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Immunity Stem cells Hemocytoblast Lymphoid stem cell Myeloid stem cell Committed cells Developmental pathway Myeloblast Promyelocyte Myeloblast Myeloblast Promyelocyte Promyelocyte Eosinophilic myelocyte Basophilic myelocyte Neutrophilic myelocyte Eosinophilic band cells Basophilic band cells Neutrophilic band cells Eosinophils Basophils a b Neutrophils c Granular leukocytes mast cells Monoblast Lymphoblast Promonocyte Prolymphocyte Monocytes Lymphocytes e d Agranular leukocytes Some become Some become dendritic cells 22 1 Innate Immunity non specific Decrease speed of or inhibits invasion 1st line of defense Physical barriers prevent entry or remove particles Skin tears saliva mucous membranes mucus 2nd line of defense Chemical mediators promote phagocytosis and inflammation Responses you are born with Adaptive immunity specific last line of defense Specificity of a particle Slower to react than innate system Responses you develop throughout life Innate Immunity protective barriers Protective chemicals inhibit or destroy microorganisms Skin acidity Lipids in sebum and dermcidin in sweat HCl and protein digesting enzymes of stomach mucosae Lysozyme of saliva tears mucus breast milk Respiratory system modifications Mucus coated hairs in the nose Cilia of respiratory tract sweep dust and bacteria laden mucus from respiratory passages Innate Immunity chemical mediators Phagocytes Inflammatory responses Antimicrobial proteins complement proteins Pyrogens Fever Innate Immunity chemical mediators Phagocytes Macrophages develop from monocytes to become the chief phagocytic cells Free macrophages wander through tissue spaces E g alveolar macrophages aka dust cells Fixed macrophages are permanent residents of some organs E g Kupffer cells liver and microglia brain Neutrophils Fist on site short lived hrs Dendritic cells not WBC Innate Immunity chemical mediators Inflammatory Response Basophils and mast cells Promote inflammation when activated by innate or adaptive system Basophils are motile leave blood and enter infected tissues Mast cells are non motile in C T Eosinophils leave blood and enter tissues Reduce inflammation by breaking down chemicals produced by basophils and mast cells Secrete enzymes that kill some parasites Innate Immunity chemical mediators Inflammatory Response contd Triggered with tissue injury or infection Prevents the spread of damaging agents Disposes of cell debris and pathogens Sets the stage for repair Cardinal signs of local inflammation Redness Heat Swelling Pain and sometimes loss of function Innate Immunity chemical mediators Inflammatory Response contd Systemic inflammatory Response same as acute local Increase in neutrophil numbers Fever dt pyrogens Widespread increased vascular permeability dt histamines Large volume of plasma enters interstitial spaces leading to hypovolemic shock Innate Immunity chemical mediators Inflammatory chemicals cause Dilation of arterioles resulting in hyperemia Increased permeability of local capillaries and edema leakage of exudate Exudate Brings in large quantities of oxygen and nutrients needed for repair Allows entry of clotting proteins to minimize spread of infection Moves foreign material into lymphatic vessels Innate defenses Internal defenses Inflammatory chemicals diffusing from the inflamed site act as chemotactic agents Chemotaxis Neutrophils follow chemical trail 4 Capillary wall Basement membrane Endothelium Leukocytosis Neutrophils enter blood from bone marrow 1 Margination Neutrophils cling to capillary wall 2 Diapedesis Neutrophils squeeze out of capillaries 3 Innate Immunity Antimicrobial Proteins Complement proteins 20 blood proteins in circulation in inactive form Major mechanism for destroying foreign substances Kills bacteria by cell lysis Utilizes both innate and adaptive immunity Innate Immunity Antimicrobial Proteins Complement proteins Alternative pathway part of innate immunity Attract macrophages Classical pathway part of adaptive immunity Requires antibodies bound to antigens Activated complement proteins Form membrane attack complexes MAC holes in plasma membrane Attach to surface of bacterial cells stimulate phagocytosis Attract immune system cells to site of infection and promote inflammation Pyrogens Systemic response to invading microorganisms Secreted by WBCs and macrophages exposed to foreign substances Benefits of moderate fever Causes the liver and spleen to sequester iron and zinc needed by microorganisms Increases metabolic rate which speeds up repair Increases efficiency of immune systems High fevers are dangerous because heat denatures enzymes E g cytokines IL 1 22 13 Adaptive Immunity Specific systemic and has memory Activates inflammatory response Two separate overlapping types Humoral Antibody mediated B cells Cellular Cell mediated T cells Stimulated by Antigens usu large complex foreign molecules that stimulates adaptive defenses Foreign Microbes Pollen animal dander feces of mites foods drugs etc Self antigens produced by body as markers to identify self Reaction to self antigens can cause auto immune diseases Haptens non immunogenic but when combined to something exacerbates an antigenic response Adaptive Immunity Antigens Self antigens cell surface proteins e g MHC Antigenic to others in transfusions or grafts Classes of MHC proteins Class I MHC proteins found on virtually all body cells Class II MHC proteins found on certain cells in the immune response ie antigen presenting cells APC B cells macrophages dendritic cells MHC proteins display peptides including self antigens In infected cells MHC proteins display fragments of foreign antigens Adaptive Immunity cells Two types of lymphocytes T lymphocytes T cells mature in the Thymus and are responsible for cell mediated immunity B lymphocytes B cells mature in the Bone marrow humoral immunity o When mature immunocompetent able to bind to a specific antigen o Immunocompetent but naive unexposed B and T cells are exported to 2 lymphatic organs lymphoid organs nodes tonsils spleen etc Adaptive Immunity cells Antigen Presenting Cells APCs Do not respond to specific antigens Engulf antigens Present fragments of antigens to be recognized by T cells Major types Dendritic cells in connective tissues and epidermis Macrophages in connective tissues and lymphoid organs B cells 22 17 Adaptive Immunity Humoral Immunity Antigen challenge First encounter between an antigen and a naive immunocompetent lymphocyte Usually occurs in the spleen


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