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125 Cards in this Set
- Front
- Back
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what are the stron physical barrier to infection?
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skin, hair, nails
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what is a volnurable physical barrier, that is more open to infection than skin?
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the mucosal linings of the respiratory and gut tracts
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What is the first line of defense against microbial attack?
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skin or mucous membranes
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What are the APC's (antigen presenting cells) that are found in the skin?
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Langerhans Cells
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What role do fluids such as urine, saliva, and tears play in pretection from microbes?
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they washe away and dilute invading microbes to ensure none can colonize the surfaces they protect
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what are the 3 components of saliva which aid in is antibacterial function?
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1. lysozyme
2. lactoferrin 3. IgA |
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what are the 3 components to the internal innate immune defense?
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1. blood-borne macromolecules (complements)
2. macrophgaes and neutrophils 3. natural killer cells |
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what immune defense allows for protection from specific invaders?
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adaptive immune response
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what are the 5 distinct properties of the adaptive immune response?
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1. specificity
2. diversity 3. memory 4. self-imitation 5. tolerance |
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What are the 3 main types of cells that participate in the adaptive immune response?
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1. B cells
2. T cells 3. specialized macrophages called (antigen presenting cells or APC's) |
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what allows for the cells of adaptive immunity to communicate with each other?
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cytokines
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what triggers the release of cytokines from adaptive immune response cells?
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presence of an antigen
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what are the predominant cells of the lymphoid system?
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B and T lymphocytes
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the location of T cells within a secondary immune organ is called?
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thymic-dependent zone
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the location of B cells within a secondary immune organ is called?
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bursa-dependent zone
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what is another name for a NK cell?
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large granular lymphocyte
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what population of lymphocytes do NK cells belong to?
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null cells
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what are the 2 major morphological differences between NK cell and B/T cells?
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1. NK cells are larger
2. NK cells have azurophilic granules |
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what is the role of the NK cells?
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kill some virally and tumor altered cells
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what restriction is lacking in NK cells that is present in CTLs?
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NK cell recognition mechanisms do not depend on MCH
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describe the specificity of NK cells?
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they are nonspecific
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what allows NK cells to use antibodies to target cells?
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the ability to recognize the Fc domain on antibodies
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what are the two modes of killing used by NK cells?
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1. release of perforins
2. use of granzymes which contain enzymes that cause apoptosis in recipient cell |
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what do NK cells have receptors for? 4
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1. IL-12
2. LPS 3. IFN-alpha 4. IFN-beta |
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what happens when NK cells bind to antigens which they are able to recognize?
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they release INF-gama which attracts and activates macrophages
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what cells will NK cells kill even though ther do not display Fc regions?
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cells with kill signals and cells that lack MHC I molecules on their cell surface
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what is the most important source of INF-gamma in the early phases of microbial invasion?
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NK cells
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how do activated macrophages respond to LPS, INF-alpha, and INF-beta?
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they become hyperactive
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what cytokine is released by active macrophages that results in the production of IL-12 by macrophages?
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TNF
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what does IL-12 cause NK cells to do?
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release IL-2
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what does IL-2 cause to happen in NK cells?
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causes the release of IFN-gamma which attracts macrophages to the site of infection
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Describe the actions of IL-2 on NK cell proliferation?
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it dramatically increases proliferation
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what are the two characteristic molecules expressed on all APC cells?
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MHC I and II
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what are most APC's derived from?
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monocytes
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APC's include what 4 cells?
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1. macrophages
2. dendritic cells 3. B cells* 4. epithelial reticular cells* *Non-monocyte derived thymus cells |
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similar to helper T cells, what do APC cells do?
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they manufacture and release cytokines
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what results in allergies associated with cutaneous contact hypersensitivity?
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IgE becomes bound to langerhans cells
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what are the most important APC's?
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dendritic cells and Langerhan's cells
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what stores antigen-antibody complexes on its PM surface to increase response by APC cells this busting the immune system?
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follicular dendritic cells (FDCs)
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the stroma of all lymphoid tissue consists of what kind of CT?
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reticular EXCEPT thymus
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what form the complex cellular framework in lymphoid tissues?
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reticular cells
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what type of collagen is found in the stroma of lymphoid organs?
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type III
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the major stromal elements of lymphoid tissue are? (2)
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1. reticular fibers
2. reticular cells |
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the major parenchymal cells of lymphoid tissue are?
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lymphocytes
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what is formed by aggregations of lymphoid cells in such places as the lamina propria of the gut?
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nonecncapsulated lymphoid tissue
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an accumulation of lymphocytes in a mucosa is characteristic of?
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chronic inflammation
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the development of diffuse lymphoid tissue below mucosal epithelium is characteristic of?
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a breach in the mucosal barrier
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what are the primary lymphoid functional units called?
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nodules EXCEPT the thymus
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what is the difference between a primary and secodary nodule?
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primary is homogenous mass of small lymphocytes while a secondary has a germinal center
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the presence of a germinal center indicates what?
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a humoral response
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what cells will be found at the germinal center?
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B lymphoblasts
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what produces the germinal center?
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antigenic stimulation
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what cells, besides the B cells, can be found in the germinal center?
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TH2 cells which are helping the blastic transformation of B cells
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what must be present in the germinal centers to clean up B cells that have undergone apoptosis?
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macrophages
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what innitiates the formation of TH2 cells that are found in the germinal centers?
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the presence of APC cells
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mature ____ cells are rarely found in the germinal center?
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plasma
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what is the major antibody formed by MALT?
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IgA
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what is oriented toward the source of the antigen and is composed of B cells in the nodule?
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lymphocyte cap
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the dense rim of B memory cells that surrounds the germinal center is known as?
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follicular mantel or corona
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how is the lymphocyte cap oriented in the spleen?
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toward the red pulp
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give 2 examples of aggregated lymphatic nodules
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1. tonsils
2. Peyer's patches |
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how many tonsils are there between the oral and nasal cavities and the pharynx?
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5
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what is the purpose of the position of the tonsils?
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to allow a reaction with antigens in the airflow through the mouth and nose and start an immune response
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what are the 3 types of tonsils?
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1. palatine
2. pharyngeal 3. lingual |
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where are the palatine tonsils found?
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between the palatoglossal and palatopharyngeal folds
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describe the structure of the palatine tonsils?
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contain cripts that collect antigen rich substances
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what is the exposed surface of the palatine tonsils covered with
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stratified squamous nonkeratinized epithelium
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where is the pahryngeal tonsil located?
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in the roof of the nasopharynx
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what structures are found on the exposed surface of the pharyngeal tonsil?
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pleats
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what opens into the base of the pleats?
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seromucous glands
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what is a swollen pharyngeal tonsil called?
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an adenoid
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where are lingual tonsils located?
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on the dorsal surface of the posterior 1/3 of the tongue
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describe the structure of lingual tonsils?
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each is a single cript which has mucous glands emptying into it
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plasma cells located below epithelial mucosa mainly produce what antibody?
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IgA
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where are Paneth cells located?
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at the base of the cripts of Leiberkuhn in the small intestine
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what is the role of the Paneth cells?
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secrete products that protect the luminal surface of the epithelium from pathogenic microorganisms
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What are the 3 major products contained in the granules of paneth cells?
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1. Tumor necrosis factor-alpha
2. lysozyme 3. defensins |
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what is Tumor necrosis factor-alpha (TNF-alpha)
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a proinflammatory substance produced in response to diverse infectious agents and tissue injury
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what is the function of lysozyme?
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to cleave peptidoglycan bonds which are found in bacteria but not human cells
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what is the function of defensins?
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antimicrobial effect by increasing the membrane permeability of a target organism through the formation of ion channels
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describe a nodule found in a Peyer's patch?
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composed of B cells surrounded by a loose region of T cells with numerous APC's
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regions of the ileum close to the lymphoid nodules of the Peyer's patches are lined by?
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M cells
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what are M cells?
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squamous like cells that capture antigens and secrete them into the underlying CT for APC's and dendritic cells
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Peyers patches are said to have no ____ lymphatic vessels?
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afferent
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lymphocytes destined for Peyer's patches are designed to migrate where?
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to the high endothelial venules (HEV)where they can leave the blood flow and enter the nodules
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when B cells return to the lamina propria the become what?
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plasma cells that produce IgA
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what two tissue are NOT drained by lymphatics?
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nervous system and bone marrow
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how do lymphatic capillaries begin?
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as blind ended pouches
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what ensures that lymphatic capillaries will not collapse and also holds the capillaries to surrounding tissue?
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anchoring filaments
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what is the distinguishing factor between blood capillaries and lymph cappilaries?
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lymph have a very sparse basal lamina
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what mechanism exists in the lymphatic VESSELS that aids in the flow of lymph from the periphery?
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valves
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what filters the lymph flowing through lymph vessels?
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lymph nodes
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what two actions allow for the "pumping" of lymph?
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1. skeletal muscle compression during movement
2. respiration |
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in large smooth muscles what additional driving force might help to push along lymphatic ducts?
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smooth muscle in the media and adventitia
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what gives lymphatic vessels a beaded appearance?
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numerous valves
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describe the relationship of lymph to lymph nodes?
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all lymph must at some point pass through a lymph node
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how many lymph nodes does the avg. person have?
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~600
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what is located on the concave surface of a lymph node?
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the hilus
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describe the numbers of afferent and efferent vessels which feed and drain the lymph nodes?
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several afferent with only 1 or 2 efferent lymph nodes
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where are the arteries and veins which supply and drain blood from the lymph nodes found?
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hilus
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describe the capsul of a lymph node?
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dense irregular connective tissue (type I collagen) with extending trabeculae
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what peirces the lymph node capsul at several points?
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afferent lymphatics
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what forms the architectural framework of the entire lymph node?
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reticular connective tissue suspended from trabeculae
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what is the outermost layer of lymphatic tissue in the lymph node called?
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the cortex
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what is housed in the cortex?
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lymph nodules
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what are the most abundant lymphatic cells in the nodules of the lymph node?
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B cells
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what occupies the parafolicullicular region of the lymph nodes?
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T cells
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the cortex represents the ____ zone of the lymph node?
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bursa-dependent
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what do some of the B cells in the germinal center undergo apoptosis and consequent degredation by macrophages?
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they have low affinity surface immunoglobulins
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what can be observed at the edges of the germinal center thaat are not derived from bone marrow?
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follicular dendritic cells
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what cells are the follicular dendritic cells interacting with in the lymph nodule?
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the mature B cells
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how are B cells rescued from apoptosis?
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a follicular dentritic cell must present an antigen to which the B cell has a high affinity immunoglobulin for
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how long can follicular dendritic cells hold on to antigen-antibodie complexes?
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weeks to months
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where is the paracortex located?
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between the nodular cortex (above) and the medulla (below)
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describe the nodules found in the paracortex?
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TRICK!!! there are none
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what are the main lymphocytes of the paracortex?
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CD4+ helper cells
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the paracortex is referred to as the ____ zone of the lymph node?
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thymus-dependent zone
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how are the helper T cells of the paracortex activated?
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APC's come to the thymus-dependent zone with epitope/MCH II complexes to present the to T cells
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newly formed T cells exit the lymph node how?
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through the medullary lymphatic sinuses
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what role do the activated helper T cells play in the bursa-dependent zone?
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they activate B cells with high affinity immunoglobulins to the antigen the helper T cell reacted with
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describe the cortex of the hilus?
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TRICK!!! over the hilus there is no cortex
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describe the structural organization of the medulla?
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organized into medullary cords of lymphatic cells sepperated by lymphatic sinuses
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what forms the medullary cords of the lymph node?
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reticular fibers secreted by reticular cells
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in addition to reticular cells, what other cells are found in the medulla? (3)
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1. plasma cells
2. macrophages 3. small lymphocytes |
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what type of antibodies are secreted directly into the medullary cords by plasma cells?
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IgM and IgG
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