Haemopoesis and the Lymphoid System Flashcards
all precursor cells come from?
haemopoietic progenitor cell which themselves derive from haemopoietic stem cells (HSC)
what are the sites of haemopoiesis from embryo to adult?
Embryo- HSC in mesoderm
Wk 5- circulating committed progenitors
Wk 6- liver starts
Wk 10- erythroid acvtivity in yolk sac stops
Wk 16- bone marrow
Adults- marrow within axial skeleton
what is polychromasia?
abnormally high number of reticulocytes
what is the name of platlet precursor cells?
megakaryocytes
what marrow is active red or yellow?
red- haemopoietically active
yellow- fatty inactive
what are the three things regulating haemopoesis?
intrinsic properties of cells (stem cells vs progenitor cells vs mature cells)
signals from immediate surroundings and periphery
speciifc anatomical area (niche) fro optimal developmental signals
how is haemopoesis assessed?
routinely undertaken blood count
morphology
bone marrow aaspirate- specialist test
which type of cells cannot be assessed using FBC?
non-lymphoid cells
what test is used to identify non-lyphoid cells?
immunophenotyping
what are the central (primary) lymphoid tissues?
boen marrow
thymus
what are the peripheral (secondary) lyphoid tissues?
lymoh nodes
spleen
tonsils (waldeyers ring)
epithelio-lymphoid tissues
bone marrow
what is chylous ascties?
accumulation of lipid rich lymph in the peritoneal cavity- due to disruption of lymphatic system secondary to trauma or obstruction
how is lymph drained from nodes?
affernet channels drain lymph through capsule
efferent vessel leaves hilum and drains to cristerna chyli or L/R jugular, subcalvian or bronchomediasteinal trunks
what is the marker for B cells?
CD20
what is the marker for T cells?
CD3
what are causes of lymphadenopathy?
inflammation due to infection
maligancy
what is castlemans disease?
benign enlargement of lymphnodes
superficial and generalised lymphadeopathy is suggestive of what?
superficial → underlyng malignancy
generalised → systemic inflammatory process or widespread malignancy
what causes a predominant B cell repsonse in lymph nodes?
auto-immune conditions
infections
what causes a predominatn phagocytic response in lymph nodes?
draining a tumour site
what causes a predominant T cell repsonse in lymph nodes?
viral infections
drugs i.e. phenytoin
what are the two surfaces of the spleen?
diphragmatic surface
visceral surface: left kidney, gastric fundus, tail of pancreasm splenic felxure of colon
desccribe red pulp in teh spleen parenchyma?
sinusoids and cords
cords in the red pulp contain what?
macrophages, firoblasts and cells in transit RBC, WBC, PC, CD8+T)
sinusoids in the red pulp are lined by what?
endothelial celss
white pulp in the spleen parenchyma comprises what?
peri-arteriolar lymphoid sheath (PALS)
describe the immune response that occurs in the white pulp of the spleen parenchyma?
antigens reach white pulp via the blood before APCs present the antigen to immune reactive cells
what are howell jolly bodies?
left over nuclear remnants usually cleared when blood cells are in the spleen- occur if no spleen or non functioning spleen
splenic vein with the SMV forms what?
portal vein
