lymphatic organs

immunocompetent

ability to recognize and respond to antigens

subscapular sinus

between the capsule and parenchyma of the lymph node; narrow, relatively clear space

spleen

body's largest lymphatic organ; erythrocyte graveyard; helps stabilize blood volume

lymphadenopathy

collective term for all lymph node diseases

white pulp

consists of lymphocytes and macrophages aggregated along small branches of the splenic artery; cylindrical

red pulp

consists of sinuses gorged with concentrated erythrocytes

tonsillar crypts

deep pits in the tonsils lined by lymphatic nodules

lymph node medulla

extends to the surface of the hilum; largely branching networks of medullary cords

germinal centers

light-staining center where B cells multiply and differentiate into plasma cells

secondary lymphatic organs

lymph nodes, tonsils, and spleen; populated with immunocompetent lympocytes only after the cells have matured

thymus

member of the endocrine, lymphatic, and immune systems; houses developing lymphocytes and secretes hormones that regulate their later activity

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

lymph node cortex

outer c-shape; encircles 4/5 of the organ; consists mainly of lymphatic nodules

tonsils

patches of lymphatic tissue located at the entrance of the the pharynx; guard against ingested and inhaled pathogens

red bone marrow

produces all classes of formed elements of the blood; involved in the hemopoiesis and immunity

primary lymphatic organs

red bone marrow and thymus; sites where B and T lymphocytes become immunocompetent

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

lymphadenitis

swollen and painful lymph node that is under challenge from a foreign antigen

parenchyma

tissue that promotes the function of the organ