Haemopoiesis Flashcards
What is the lifespan of neutrophils?
7-8 hours
What is a platelet precursor?
megakaryocyte
What is a RBC precursor?
reticulocyte
What is a erythroblast or myeloblast?
nucleated precursor cell
What is a myelocyte?
nucleated precursor between a neutrophil and a myeloblast
What do precursors arise from?
haematopoietic stem cells
What are the two routes that HSCs can go down?
myeloid or lymphoid
When does yolk sac haematopoiesis stop?
week 10
When does liver haematopoiesis start?
week 6
When does bone haematopoiesis start?
week 16
What cells are in the bone marrow?
haemopoietic cells
non haemopoietic cells - adipocytes, fibroblasts, osteoclasts, osteoblasts
What is the vasculature of the bone marrow?
venous sinuses that drain arterioles
formed blood cells pass through fenestrations in endothelial cells and enter the circulation
What is the release of RBC from the bone marrow associated with?
sinusoidal dilation and increased blood flow
neutrophils actively migrate towards the sinusoid
megakaryocytes extend long branching processes called proplatelets into sinusoidal blood vessels
What are the two types of bone marrow?
red marrow and yellow marrow
Describe red marrow?
haematopoietically active
Describe yellow marrow?
fatty inactive marrow - more of this as you age
What regulates haemopoiesis?
intrinsic properties of the cell - stem cells vs progenitor cells vs mature cells
signals from immediate surroundings and periphery
specific anatomical area for optimal developmental signals
How are non lymphoid cells assessed?
blood count
morphological assessment
How are lymphoid cells assessed?
immunophenotyping - expression of antigens
What is immunophenotyping?
uses antibodies specific to different antigens
