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89 Cards in this Set
- Front
- Back
structures that produce the cell components of the immune system
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primary lymphoid organs
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examples of primary lymphoid organs
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bone marrow and thymus
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in these organs, lymphocytes differentiate from lymphoid stem cells, proliferate and mature into functional cells
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primary lymphoid organs
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structures that are the sites to trap antigen from defined tissues or vascular spaces where immune responses occur
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secondary lymphoid organs
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examples of secondary lymphoid organs
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lymph node, spleen, tonsils and aggregates of lymphocytes and antigen-presenting cells in lung and mucosa of digestive track
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major cells of the lymphatic system
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lymphocytes and macrophages
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cells found in peripheral blood, lymph nodes, spleen, thymus, tonsils, appendix, and scattered in many other tissues - have very little cytoplasm and round nucleus
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lymphocytes
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these cells originate in bone marrow, mature in fetal liver and bone marrow and migrate to secondary (peripheral) lymphoid organs
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B cells
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when B cells are activated, they differentiate into...
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plasma cells
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precursors of cells that produce immunoglobulins (antibodies)
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B cells
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these cells are located in CT and lymphoid tissues, but NOT found in circulation
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plasma cells
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these cells originate in bone marrow, mature in thymus, the migrate to secondary lymphoid organs like lymph nodes and spleen
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T cells
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macrophages are derived from
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blood monocytes
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macrophages in liver
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Kupffer cell
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macrophages in lung
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alveolar macrophage
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macrophages in brain
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microglia
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functions of macrophages
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phagocytosis and antigen presentation
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how are lymphatic capillary walls different from blood capillary walls?
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more permeable
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which organs lack lymphatics?
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brain, spinal cord, internal ear, cartilage, bone and bone marrow
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lymphatic vessels resemble veins with these exceptions:
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thinner walls
contain more valves lymph nodes at intervals along course intima, media and adventitia are poorly demarcated |
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collecting vessels originate as microscopic blind-end vessels called
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lymphatic capillaries
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lymphatic valves originated by
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local folding of the tunica intima
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what are the two main lymphatic ducts?
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thoracic duct and right lymphatic duct
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structure that arises in the abdomen and travels up along vertebral column through the thorax and empties into superior vena cava
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thoracic duct
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structure that is short and carries drainage from the right upper portion of the body
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right lymphatic duct
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dense localized collections of lymphocytes arranged in rounded masses that are sharply defined but not encapsulated
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lymphatic nodules
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what type of lymph nodules do not have germinal centers
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those that are in a state of rest
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primitive reticular cells give rise to what?
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medium sized lymphocytes in addition to macrophages
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4 functions of lymphatic nodule
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1. production of new lymphocytes
2. functional differentiation of B lymphocytes 3. phagocytic potential of free and fixed macrophages 4. activity against bacteria and foreign matter |
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aggregate nodules are a close grouping of lymph nodules that are present in lamina propria and are also called what?
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peyer's patches
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the top of the peyer's patch nodule facing the lumen is covered with what/
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intestinal epithelium
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aggregates of more or less encapsulated lymphatic tissue situated at the entrance of the oral and nasal pharynx
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tonsils
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structure located at the entrance to the throat
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palatine tonsil
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the palatine tonsil is composed of what types of tissue?
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diffuse and nodular lymphoid tissue
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what covers the free surface of the palatine tonsil?
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non-keratinized stratified squamous epithelium
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what lines the lingual tonsil?
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non-keratinized stratified squamous epithelium
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leukocyte infiltration is less in the lingual tonsil than in what?
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palatine tonsil
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clinical name for pharyngeal tonsils
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adenoids
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location of pharyngeal tonsils
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median dorsal wall of the nasopharynx
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epithelium of pharyngeal tonsils
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pseudostratified with cilia and goblet cells
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oval-shaped structures occurring in series along the lymphatic vessels
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lymph nodes
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what extends from the covering capsule of lymph nodes to the center of the node?
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fibrous septa or trabeculae
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trabeculae in lymph nodes separates what from each other?
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cortical nodules
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what lines both the cortical and medullary sinuses of lymph nodes?
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reticular cells and macrophages capable of phagocytosis
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cellular component/lymphoid tissue of lymph node
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parenchyma
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portion of cortical parenchyma that is adjacent to medulla and is free of nodules
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deep cortex, paracortex, or thymus-dependent cortex
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area of lymph node where lymphoid tissue is found in dense strands or cords
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medullary parenchyma
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medullary parenchyma is the chief site of what 3 structures?
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B lymphocytes, macrophages and plasma cells
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where are T lymphocytes most common in lymph node?
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paracortex (deep cortex)
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system of irregular channels lined with reticular cells
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lymphatic sinuses
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3 parts to the lymphatic sinus system
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subscapular sinus
trabecular sinus medullary sinus |
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the emigration of lymphocytes from the blood into the lymph nodes occurs only at these endothelial cells
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high endothelial venules
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largest of all lymphoid organs
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spleen
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2 types of parenchyma in spleen
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white pulp and red pulp
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channels that intervene between veins and arteries
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splenic sinuses
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surrounds and follows arteries, thickens into ovoid masses called splenic nodules
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white pulp
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what forms the periarterial lymphoid sheaths?
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white pulp
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PALS are mainly composed of what cells?
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T lymphocytes
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germinal centers are mainly composed of what cells?
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B lymphocytes
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transitional area bw white and red pulp that is looser in texture than white pulp
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marginal zone
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which area of the spleen receives the incoming arterial blood?
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marginal zone
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first site for blood borne cells and particulate matter with splenic parenchyma
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marginal zone
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this area of the splenic parenchyma consists of splenic sinuses separated by splenic cords
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red pulp
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density and firmness of red pulp depends on what?
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amount of blood present
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arterial blood flow into the spleen
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splenic artery --> trabecular arteries --> central artery (supplies white pulp) --> penicillar arterioles --> arterial capillaries --> splenic cords --> splenic sinuses
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splenic sinuses conduct blood to what structure?
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pulp veins
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splenic veins are lined with what?
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conventional epithelium and continuous basal lamina
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pulp veins converge to form what?
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trabecular veins (then splenic vein)
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7 major functions of spleen
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1. form RBCs during fetal life
2. Remove and destroy damaged RBCs 3. Retrieve iron from red cell hemoglobin 4. generate lymphocytes and monocytes 5. filter blood 6. actively phagocytize bacteria 7. produce antibodies |
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broad, flat bilobed mass of lymphoid tissue enclosed by a connective tissue capsule
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thymus
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first organ to become lymphoid during embryonic life
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thymus
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cortex parenchyma of the thumus consists of what cells?
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lymphocytes, reticular cells and macrophages
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this area of the thymus consists of a concentric mass of epithelioreticular cells joined together by many desmosomes
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medulla
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distinguishing feature of the thymus
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hassall's corpuscles
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isolated mass of closely packed, concentrically arranged type VI epithelioreticular cells
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hassall's corpuscles
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hassall's corpuscles produce ______ that function in differentiation and maturation of T lymphocytes
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interleukins
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what protects developing T lymphocytes from exposure to antigens?
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blood-thymus barrier
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components of blood-thymus barrier
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1. endothelium and its basal lamina
2. macrophages in perivascular tissue 3. type I epithelioreticular cells with their basal lamina |
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major function of the thymus
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differentiation and proliferation of t-lymphocytes
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thymus is eventually replaced by what?
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adipose tissue
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produce antibodies in response to cell-free and cell-bound antigens
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B lymphocytes
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20-30% of circulating lymphocytes
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B lymphocytes
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60-80% of circulating lymphocytes
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T lymphocytes
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respond to cell-bound antigens (viral, fungal infected, and tumors)
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T lymphocytes
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5-10% of circulating lymphocytes
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NK (natural killer) cells
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stroma
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reticular fibers and cells
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diffuse lymphatic tissue is mainly found where?
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GI tract and respiratory tract
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sites of B lymphocyte proliferation
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germinal centers
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aggregated lymphatic nodules in ileum
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peyer's patches
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