Chapter 1 in
haematology (haemopoiesis)summary
-Haemopoiesis (blood cell formation)arises form pluripotent stem cells in the bone
marrow.stem cells give rise to progeitor cells which,after cell divisions and
differetiatio,form red cells,granulocytes.(neutrophils,eosinophils and
basophils).monocytes,platelets and B and T lymphocytes.
- Haemopoetic tissue pccupies about 50% of the bone marrow space i normal adult
marrow.haemopoiesis in adults is confined to the central skeleton but in
infants and young chlidre haemopoietic tissue extends down the lng bones of the
arms and legs .
-Stem cells reside
in the bone marrow in niches formed be stromal cells anf circulate i the blood.
-Growth factors attach to specific cell receptors ad produce a cascade of
phosphorylation events to the cell nucleus .Transcription factors carry tha
massage to those genes that are to be "switched on", to stimulate
cell division,differentiation,functional activity or suppress apoptosis.
-Transcription factors are molecules that bind to DNA and control the transcription of
specific genes or gene families.
-Apoptosis is a
physiological process of cell death resulting from activation ratio of
pro-apoptotic proteins to anti apoptotic proteins determines the cell
suscepitbility to apoptosis.
-Adhesion molecules are alarge family of glycoproteins that mediate attachment of marrow
precursors and mature leucocytes and plateles to extracellular
matrix,endothelium and to each other .
From book: Essentail Haematology A.V.HOFFBRAND,P.A.H.MOSS.6EDITION
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