Haemopoiesis and The Lymphoid System Flashcards
what is the name for when there is too many blood cells
Myeloproliferative disorders
what is the progression from premature cell to neutrophil
myeloblast»_space; promyelocyte»_space; myelocyte»_space; metamyelocyte»_space; neutrophil
what is the precursor cell of platelets
megakayocyte
- polyploid [can undergo division w/out cytoplasm dividing]
what is meant by “blasts”
primitive nucleated precursor cell
what are haemopoietic cells derived from
mesoderm
where is the first site of erythroid activity
yolk sac
- stops by week 10
where are the other sites of erythroid activity
Liver starts by week 6
Spleen by week 12 (small contribution in humans)
Bone marrow by week 16
after age 20, where are the main sites of haemopoiesis
axial skeleton
- skull, ribs, sternum, vertebra
what are the bone forming cells and what are the bone break down cells
bone forming = osteoblasts
bone break down = osteoclasts
how does blood enter the bone
arteries feed into sinusoids
what are sinusoids
flatten capillaries with holes between epithelial cells which all regulation of which cells get in and out the blood vessels
why are sinusoids important
Formed blood cells can pass through gaps in endothelial cells to enter circulation
what is the relationship between megakaryocytes and sinusoids
extend long branching processes called proplatelets into the sinusoidal blood vessels
- blood sheers off platelets and they enter the blood stream
what is red and yellow marrow
red = haemopoietically active
yellow = fatty inactive
what is the composition in marrow as we get older
red marrow replaced by yellow marrow
what is meant by the myeloid:erythroid ratio
relationship of neutrophils and precursors to proportion of nucleated red cell precursors
what is neutrophil maturation regulated by
G-CSF (granulocyte-colony stimulating factor)
what regulates growth and development of megakaryocytes from precursors
Thrombopoietin
what is important for cytokine growth
stem cell factor
what is important for stem cell development
CXCL12
what investigation is the study of antigen expression using specific antibodies
immunophenotyping
[using flow-cytometry]
what is the functions of the lymphatic system
Return lymph to the circulation
Filter lymph before return to the circulation
what is lymph nodes ensures unidirectional flow
valves
what cells are seen in lymph nodes
Lymphocytes
- B cells, T cells [helper or cytotoxic] and NK cells
Mononuclear phagocytes (macrophages), APC, and dendritic cells.
Endothelial cells
what is a marker for a B-cell
CD20
what is a T-cell marker
CD3
what are causes of lymphadenopathy
local inflammation
systemic inflammation [infection, autoimmune, CTD]
malignancy
what could a lymphadenopathy of predominant B-cells mean
autoimmune conditions
infections
what could a lymphadenopathy of predominant phagocytic response mean
draining a tumour site
what could a lymphadenopathy of predominant T cell mean
Viral infections
Drugs e.g. Phenytoin
what is a malignant lymphadenopathy called
lymphoma
what is the blood supply of the spleen
splenic artery
- branch of coeliac axis
what is the venous drainage of the spleen
splenic vein
- w/ SMV forms portal vein
what does the parenchyma of the spleen include
red pulp and white pulp
what does the red pulp in the spleen contain
sinusoids
- lined by endothelial cells with gaps
and cords
- contain macrophages, some fibroblasts
what does the white pulp do in the spleen
comprises the peri-arteriolar lymphoid sheath (PALS).
- CD4+ lymphoid cells
how does PALS work
Antigen reaches white pulp via the blood.
APCs in the white pulp present antigen to immune reactive cells
When stimulated by antigen, T and B cell responses may occur
what is features of splenic enlargement
Dragging sensation in LUQ
Discomfort with eating
Pain if infarction
Hypersplenism
what is the triad of hypersplenism
- splenomegaly
- fall in one or more cellular components of blood
- correction of cytopenias by splenectomy
what can cause hyposplenism
splenectomy
coeliac disease
sickle cell disease
sarcoidosis
what are features of hyposplenism
Howell-Jolly bodies
what do people need to be immunised against if the spleen is taken out
pneumococcal s
what is lymphoma
malignant lymphocytes that accumulate in the lymph node
what are the subdivisions of lymphomas
Hodgkin Lymphoma
Non-Hodgkin Lymphoma
what are symptoms of a lymphoma
painless, non-tender, rubbery/soft, asymmetrical lump - NOT TETHERED
fever night sweats weight loss itch w/out rash alcohol induced pain fatigue
how would a viral lymphadenopathy present
tender, hard and smooth lymph node
how would a bacterial lymphadenopathy present
tender, hard, and smooth lymph node
skin inflammed
how would a metastatic lymphadenopathy present
non-tender, hard lymph node with a irregular surface
TETHERED
how is a lymphadenopathy investigated
FNA or core biopsy
after a lymphoma has been confirmed, what Ix can be done to help subclassify
immunohistochemistry
what are the 4 subtypes of Hodgkin’s disease that can be differentiated from histology
Nodular Sclerosis
Lymphocyte rich
Mixed cellularity
Lymphocyte depleted
what cell type is associated with Hodgkin’s disease
Reed Sternberg cells
what immunomarker is positive in follicular Non-Hodgkin’s lymphoma
CD20
what immunomarkers are positive in Reed Sternberg cells
CD30 and CD15
what are the two types of NHL
T cell NHL (10%)
B cell NHL (90%)
what is a B cell NHL furthered divided into
Low grade B cell
High grade B cell
how is lymphoma staged
1 = one group of glands above diaphragm
2 = more than one group of glands EITHER above OR below diaphragm
3 = both above and below diaphragm
4 = extra nodal disease
