Lymphoid system* Flashcards
origins of lymphoid cells
haemoatopoietic stem cells -> precursor lymphoid cells -> bone marrow and thymus -> secondary lymphoid organs
primary lymphoid tissue
bone marrow
thymus
secondary lymphoid tissues
LNs spleen tonsils (waldeyers ring) epithelial-lymphoid tissues bone marrow
why is lymph returned to the circulation
important function in fluid homeostasis
prevent excessive accumulation of fluid in tissues - oedema
why is it filtered before returning to the circulation
cell traffic
interactions with immune competent cells - protective function
lymph nodes are what
size
where
function
small oval bodies
up to 2.5cm
along course of lymphatic vessels
transport fluid back to circulation
LN filtering
lymph is filtered within the node parenchyma before return to the blood stream
cells in LNs
B cells
T cells
macrophages, antigen presenting cells, dendritic cells
endothelial cells
when stimulated what happens from b cells
go from primary follicles to secondary follicles
LN enlargement
lymphadenopathy
localised or generalised
peripheral or central
causes of ln enlargement
reactive neoplastic local inflam sysetmic infection malig
superficial infection - red lines from an inflamed lesion
lymphangitis
regional lymphadenopathy can be what
underlying malignancy?
generalised lymphadenopathy
systemic inflam process or widespread malig - lymphoma/leuk
predom B cell response
predom phagocytic response
predom T cell response
AI conditions, infections
draining a tumour site
viral infections, drugs (phenytoin)
