Term
| classes of pathogens that immune system protects against |
|
Definition
| 1. bacteria; 2. viruses; 3. fungi; 4. parasites |
|
|
Term
|
Definition
| 1. surface wound introduces bacteria which activates effector cells (macrophages) to release of cytokines and immunity mediators; 2. vasodilation and increased vascular permeability allows fluid, protein, and cells to leave blood and enter tissue (esp neutrophils and macrophages are attacted to the area); 3. infected tissue becomes inflamed-redness, heat, swelling, and pain, moncytes come in and become macrophages to create a positive feedback loop (too much cytokines have unhealthy side effects) |
|
|
Term
|
Definition
| 1. monocyte-circulating precursor to macrophage has bilobed nucleus; 2, macrophage-involved in phagocytosis and killing of microorganisms-also in activation of T cells and initiation of immune responses (ratio of cytosol to nucleus increased and there are bluish granules that are toxic); 3. Natural killer cells-kills cells infected with certain viruses; 4. neutrophil-phagocytosis and killing of microorganism is a lymphocyte are most numerous in site of infection and have short life span |
|
|
Term
| abundance of leukocytes in peripheral blood |
|
Definition
| neutrophil (40-75%), eosinophil (1-6%), basophil (<1%), monocyte (2-10%), lymphocyte (20-50%-mediating other branc of immune response) |
|
|
Term
| cells arising from myeloid progenitor |
|
Definition
| 1. neutrophils, eosinophils, basophils; 2. dendritic cells, mast cells, macrophages |
|
|
Term
|
Definition
| include plasma cells (fully differentiated B cell that secretes antibodies-large amount of cytoplasm with RER and Golgi for Ig production); effector T cells (helper and cytotoxic) and natural killer cells (innate response) |
|
|
Term
| characteristics of innate immunity |
|
Definition
| must be rapid response and these cells carry receptors to recognize signs of any pathogen; limited number of specificities and constant during response so doesn't allow for improvment after the organism is rechallenged and responds as it did before because of lack of specificity |
|
|
Term
| characteristics of adaptive immunity |
|
Definition
| slow response takes days to weeks and needs participation from innate immunity; each lymphocyte can recognize only one certain structure-very highly specific and this allows for improved response to learn and response more quickly in subsequent challenges |
|
|
Term
| receptors of innate immune response |
|
Definition
| have TLR (toll-like receptors) that recognize specific aspects of a pathogen-including outer membrane of gram negative bacteria, gram positive, host proteins that are not normally exposed (shows cell has died); flagellin, and DNA |
|
|
Term
|
Definition
| one cell has a certain specificity and recognizes a small structured part of the pathogen (usually 6-7 amino acids) and the cells gets activated and differentiates and proliferates to form clones that recognize that pathogen |
|
|
Term
|
Definition
| primary response-occurs after first exposure to an antigen has a lag phase for clonal expansion and differentiation to produce antibodies and also form memory cells that have a long life span and have many more baseline cells to react to pathogen; secondary response-re-exposure to same pathogen causes a much faster response due to these memory cells and the antibody secretion is sharp and stays for a extended period |
|
|
Term
|
Definition
| the B cell has a membrane bound Ig that is a receptor for an antigen; the B cell encounters an antigen and gives rise to plasma cells that secrete antibodies that are same specificity as the membrane Igs expressed by the B cell precursor |
|
|
Term
|
Definition
| 1. have a light chain and a heavy chain with an N-termini region and C-termini region connected by disulfide bonds; 2. also have a variable region and a variable region with the variable region acting as the antigen binding site while the constant region remains the same in all B cells |
|
|
Term
| types of epitopes recognized by the antibody |
|
Definition
| 1. linear epitope-where the amino acids are in a row on the protein antigen; 2. discontinuous epitope-recognizes amino acids in the protein antigen that may not be in sequence but are near each other as a consequence of protein folding |
|
|
Term
| diversity in B cell genes |
|
Definition
| gene segments rearrange in the course of B cell development and in this rearrangement choose only one D and J segments which become joined with V segment to form mature gene for Ig; in each chain there is a wide variety of Variable (V), Diversity (D), and Joining (J) segments that give rise to 10^14 different Igs |
|
|
Term
|
Definition
| 1. cytotoxic T cell-has CD8 and recognizes virus-infected cell and causes its death; 2. helper T cells-have CD4 recognize antigens on antigen presenting cells and release soluble factors to mediate immune response (macrophages or B cells) |
|
|
Term
| similarities between T cell receptor and B cell Ig |
|
Definition
| both have varible and constant region and antibody binding site and both are formed by gene rearrangement of the germline DNA to create variability |
|
|
Term
| major difference with T cell activation |
|
Definition
| need antigen presentation by MHC receptors and needs CD4/CD8 molecule to mediate the reaction between MHC-antigen-T-cell receptor and it increases the overall affinity of the complex |
|
|
Term
| presentation of exogenous peptides |
|
Definition
| an antigen is taken up by macrophages and broken down in phagolysosome; the MHC class II binds with the peptide and presents the antigen on the surface of the cell; has beta (1,2) and alpha (1,2) sections |
|
|
Term
| endogenous peptide presentation |
|
Definition
| the antigen is degraded in proteosome and peptide is transported into the ER where it combines with MHC class I and it is presented on the surface of the cell threes alpha segments; occurs with virus infected cells |
|
|
Term
|
Definition
| B cells-develop in the bone marrow and mature in the various lymphatic organs; T cells-precursors are formed in the bone marrow and migrate to the thymus where it matures and then goes to the various structures |
|
|
Term
| general structural organization of lymphatic organs |
|
Definition
| meshwork of reticular fibers and reticular cells supporting many lymphocytes (in lymph node, tonsil and spleen but not the thymus); blood is processed in the spleen in the meshwork and lymph is processed in lymph nodes and phagocytes and lymphoid cells of immune response remove undesirable results |
|
|
Term
|
Definition
| tissues where maturation of the lymphocytes occurs (thymus and bone marrow, also fetal liver) |
|
|
Term
| secondary lymphoid tissue |
|
Definition
| tissues where lymphocytes recognize foreign antigens (lymph nodes, spleen, MALT, cutaneous-associated lymphoid tissue |
|
|
Term
| capsulation of the thymus |
|
Definition
| consists of lobes and completely encapsulated and CT extends inward to subdivide it into thousands of lobules each containing some medulla and cortex; internal support provided by epithelial-reticular cells and joined together by desmosomes and contain tonofilaments and secretory granules |
|
|
Term
|
Definition
| epithelial cells that form a cytoreticulum that is tightly packed with lymphocytes and underlie the capsule and envelop the thymic blood vessels |
|
|
Term
|
Definition
| enter thymus from surrounding CT and pass between lobules carry surrounding CT and layer of epithelialreticular cells along with is basal lamina; makes the blood-thymus barrier impervious to particulate and protein tracers and excludes antigens from influencing T cell development (stem cells and T cells can migrate across this) |
|
|
Term
| other cells in the thymus |
|
Definition
| macrophages found in cortex and medulla and function to rid the organ of great excess of lymphocytes produced and engulf any potential antigens |
|
|
Term
| maturation of T cells in the thymus |
|
Definition
| enter thymus via capsule or septa and in the cortex the T cells are undergoing positive selection and only cells that can recognize MHC are allowed to survive (rest eliminated by apoptosis);these cells then move to the medulla where they undergo negative selection and they interact with dendritic cells and macrophages and those cells showing low affinity for self peptides are allowed to survive; about 95-99% of lymphocytes will die by apoptosis |
|
|
Term
| hormones of T cell maturation and differentiation |
|
Definition
| thymosin, thymopoietin and cytokines (IL-7) |
|
|
Term
| general lymph node characteristics |
|
Definition
| major clusters located in neck, axilla, groin, and para-aortic area; those that protect the skin are called subcutaneous and those that protect the mucosa of respiratory, GI and GU are called visceral nodes |
|
|
Term
| capsular surrounding the lymph node |
|
Definition
| CT capsule which has fibrous trabeculae extending into the node and penetrated by several lymphatic vessels which empty the lymph into a subcapsular and medullary sinus; subcapsular sinus lined by endothelial cells and phagocytic cells |
|
|
Term
|
Definition
| composed of outer cortex of B lymphocytes which are localized in primary follicles and paracortex which contains sheets of T cells and interstitial dendritic cells; some follicles have germinal centers |
|
|
Term
| flow of lymph through lymph node |
|
Definition
| afferent lymphatic vessels pour lymph into sucapsular sinus which drain into the travecular sinuses which continue to sinuses between medullary cords and then the lymph leaves through efferent lymphatics at the hilus; sinuses are lined by endothelial cells that are tightly joined without gaps or pores |
|
|
Term
| blood supply of lymph node |
|
Definition
| has arterial and venous supply at the hilum- arterial vessels enter and divide in the medulla and form capillary networks in cortex and paracortex and post capillary venules are high endothelial venules (HEVs) which are cuboidal and express lymphocyte-homing receptors where the T cells enter the lymph node and encounter antigen by APC |
|
|
Term
|
Definition
| cords of less dense lymphoid tissue (plasma cells, macrophages and scattered lymphocytes) seperated by medullary sinuses lined by pale staining endothelial cells |
|
|
Term
| functions of the lymph node |
|
Definition
| filter to eliminate microorganisms and provide a site of interaction between lymph and blood allow recognition of antigen presented by APC to lymphocytes and generation of clones |
|
|
Term
|
Definition
| filters blood to remove blood-borne antigens, remove aged or abnormal red cells as well as platelets from circulation and serve as resevior for erythrocytes and platelets |
|
|
Term
| general characteristics of spleen |
|
Definition
| capsule is dense and thick collagenous structure and traceculae extend internally; spleen consits of red and white pulp seperated by diffuse marginal zone (70-75% red pulp) |
|
|
Term
|
Definition
| has two parts pulp cords filled with diffuse lymphoid tissue containing erythrocytes, platelets, granulocytes, lymphocytes and plasma cells and between these cords are thin-walled vascular sinuses filled with blood |
|
|
Term
|
Definition
| splenic artery enters at hilus and branches travel in trabeculae which finally branch and enter pulp and become ensheathed by sleeve of lymphocytes (white pulp-at center which is central artery) |
|
|
Term
|
Definition
| aggregated tissue of T and B cells and T cells are are located around central arteries forming periarterial lymphoid sheaths; B cells form follicles including germinal centers located near an arteriole |
|
|
Term
|
Definition
| border between red and white pulp which consists of lymphocytes and dendritic APC where activation takes place |
|
|
Term
| termination of arteries in red pulp |
|
Definition
| either directly connecting to venous sinuses or freely into cords; the central artery forms pannicular arterioles and open ends surrounded by macrophages (sheath capillaries) |
|
|
Term
|
Definition
| long anastomosing channels composed of thick endothelial cells between which tight junctions occur and these cells are surrounded by amount of basal lamina and reticular fibers have slits between them that allow blood from pulp cords to return to the vascular system; normal RBCs move in and out quickly but aged or damaged ones are detained and destroyed in red pulp by macrophages |
|
|
Term
| loose lymphatic infiltration |
|
Definition
| collections of lymphocytes infiltrating into any tissue where inflammation exists number varies |
|
|
Term
| dense lymphatic accumulations |
|
Definition
| solitary lymphatic nodules frequently with germinal centers |
|
|
Term
|
Definition
| hundreds of lymphoid nodules underlying certain eptihelial surfaces (Peyers patches, appendix, and tonsils) only partial CT capsule have efferent lymphatic vessels but no afferent; filtration, lymphocyte production and immunological responses |
|
|
Term
|
Definition
| generation of immune response to foreign antigens present in the lumen; M cells specialize epithelial cells are present to endocytose the antigen into pocket of M cells where immune response is initiated |
|
|
