Haematology summray 1

Haematology summray 1

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