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20 terms

lymphatic organs

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primary lymphatic organs
red bone marrow and thymus; sites where B and T lymphocytes become immunocompetent
immunocompetent
ability to recognize and respond to antigens
secondary lymphatic organs
lymph nodes, tonsils, and spleen; populated with immunocompetent lympocytes only after the cells have matured
red bone marrow
produces all classes of formed elements of the blood; involved in the hemopoiesis and immunity
thymus
member of the endocrine, lymphatic, and immune systems; houses developing lymphocytes and secretes hormones that regulate their later activity
reticular epithelial cells
seal off the cortex from the medulla and surround blood vessels and lymphocyte clusters in he cortex; develop the blood-thymus barrier; produce several signaling molecules that promote development and action of T cells
lymph nodes
most numerous lymphatic organ; cleanse the lymph and act as a site for T and B cell activation; only lymphatic organ with afferent lymphatic vessels; especially populated in the following regions: cervical, axillary, thoracic, abdominal, intestinal, inguinal, and popliteal.
subscapular sinus
narrow relatively clear space which contains reticular fibers, macrophages, and dendritic cells
germinal centers
light-staining center where B cells multiply and differentiate into plasma cells
lymphadenitis
swollen and painful lymph node that is under challenge from a foreign antigen
lymphadenopathy
collective term for all lymph node diseases
tonsils
patches of lymphatic tissue located at the entrance of the the pharynx; guard against ingested and inhaled pathogens
tonsillar crypts
deep pits in the tonsils lined by lymphatic nodules
spleen
body's largest lymphatic organ; erythrocyte graveyard; helps stabilize blood volume
red pulp
consists of sinuses gorged with concentrated erythrocytes
white pulp
consists of lymphocytes and macrophages aggregated along small branches of the splenic artery; cylindrical
parenchyma
tissue that promotes the function of the organ
lymph node cortex
outer c-shape; encircles 4/5 of the organ; consists mainly of lymphatic nodules
lymph node medulla
extends to the surface of the hilum; largely branching networks of medullary cords
subscapular sinus
between the capsule and parenchyma of the lymph node; narrow, relatively clear space