Presentation on theme: "Pathology Dept/ Sulaimani School of Medicine /University of Sulaimani"— Presentation transcript:
1Pathology Dept/ Sulaimani School of Medicine /University of Sulaimani HemopoiesisDr. Sana D. JalalM.B.Ch.B/F.I.B.M.S.PathPathology Dept/ Sulaimani School of Medicine /University of Sulaimani
2Haematology: is the study of the blood and its diseases Blood : is a suspension of non-dividing end-stage cells of three types namely, red cells (erythrocytes), White cells (leucocytes) and platelets (thrombocytes). The suspending fluid is the Plasma.
7Simplified chart of hemopoeisis from Stem cell to end stage cells Stem cell COMMITMENT PrecursorsMultipotential Stem cellsErythroid precursorsProerythroblastsRBCPluripotential Stem cellsMyeloid precursorsMyeloblastsNeutrophilMegak-aryocytePrecursorsfor megak.PlateletsLymph nodesCourtesy of Professor Nasir AllawiB or T LymphocytesLymphoid Stem cells
11The Concept of STEM CELLS Stem cells are cells from which all Hemopoietic elements originate. They are characterized by their ability of Self-renewal & Differentiation.Stem cells require for their proliferation and differentiation :- Certain regulatory factors (Hemopoietic Growth Factors).- Suitable microenvironment, provided by the marrow space.Stem cells Precursors End-stage cellsThe End stage cells have a restricted life span, ranging from 4 months for RBC, days for platelets, hours for granulocytes. These cells have to be continuously replaced by bone marrow, and BM should produce daily some 2.5 billion red cells/kg, 2.5 billion red cells/kg platelets, and 1 billion granulocytes/kg. Actually any normal individual will produce a no. of hemopoietic cells equivalent to his body weight /year, to maintain his peripheral blood counts.
12Myeloid Hemopoietic System The earliest evidence of myelopoiesis ( mesoblastic phase) occur in the yolk sac of the embryo.In this stage the hemopoietic system consists primarily of mesenchymal derived primitive erythroblast.The hepatic phase begins in the second month of fetal life.( megakaryocytes and granulocytes appears in the sinusoids of liver)At wks gestation , the liver is the principle site of hemopoiesis till approximately 24 wks.Bone marrow function starts from the 4th – 5th months of gestation and is the major site of Hemopoiesis till birth.
13Myeloid Hemopoietic System Myeloid hemopoietic system in normal individual in the first yr. of postnatal life is in both axial and radial skeleton.Thereafter, there is a gradual regression of the hemopoiesis in the long bones until about the age of 15 , when the flat bones of the central skeleton ((pelvis, vertebral column, cranium, ribs ,sternum), and epiphysis of long proximal bones are the exclusive sites of hemopoiesis.The BM in postnatal life comprises about 3.5%-6% of total body weight and in aggregate mass approximates the size of liver.
14Structure of Bone Marrow Bone Marrow Consist of Hemopoietic tissue, adipose tissue and stroma.The stroma consist of delicate framework of connective tissue.The vascular supply is derived from the nutrient artery which ramify through the marrow space.The arterioles of the nutrient artery branch into capillaries which are continuous within a system of thin walled of sinusoids.The adventitial reticular cells synthesize the extravascular collagen and adhesive protein.
16Microscopical Features: Erythroblasts or normoblastsMicroscopical Features:Reduction in the cell size.Loss of nucleoli.Clumping of nuclear chromatin.Hemoglobinization of the cytoplasm.Loss of nuclei.ProerythoblastReticulocyteEarlyintermediatelateMature RBCProerythoblastThe earliest Erythroid recognizable cell is the Proerythroblast, which is large cell with high N/C ratio, basophilic cytoplasm, and open nuclear chromatin with prominent nucleolus. The next stage is early normoblast, in which the cell loses its nucleolus, but cytoplasm remains blue. The next stage is the intermediate normoblast in which the N/C ratio gets smaller, while the cytoplasm becomes less basophilic, as Hb increases.while the nuclear chromatin becomes more condensed and clumped The next stage is the late normoblast in which the cytoplasm become more pink due to Hbinization, and nuclear chromatin more condensed. The nucleus is then extruded to form a reticulocyte, which remains normally about two days in the marrow and is then released to circulation and matures finally into a mature anucleated erythrocyte.Normoblasts Intermediate LateRed Cell precursors (in marrow)
17Microscopical Features: Reduction in the cell size.Loss of nucleoli.Granulation of cytoplasm ( primary and secondary).Nuclear segmentation.Stages of Maturation of the Granulocytic SeriesIn the bone marrowBloodBone marrow
20Leucocytes in BloodLeucocyte counts range in a normal adult between 4-10 x 109/L.Normally majority of the cells seen are neutrophils, followed by lymphocytes, monocytes, eosinophils and basophils.Determination of the proportion of various leucocyte types in the blood is called Differential leucocyte count.
21Terms used to denote changes in leucocytes numbers: Leucocytosis : increased no. of leucocytes above 10.0 x 109/L.Leucopenia : Reduced total leucocyte count below 4.0 x 109/L.
22Megakaryocyte : the precursor of Platelets in the marrow Microscopical Features:Increased cell size.Lobulation of the nuclei.Cytoplasmic granulation.
23Platelets in blood Platelets count normally ranges between 150 to 450 x 109/L.Increased Platelets above 450 is called thrombocytosis.Reduced Platelets below 150 is called thrombocytopenia.
24Life span of blood cells in peripheral circulation - Red cells : 120 days.- Granulocytes : ~ 1day.- Platelets : 7-10 days.
26Bone marrow examination In certain conditions a bone marrow examination is required for diagnosis or follow-up of patients. There are two types of marrow procedures :1. Bone marrow aspirate : done from iliac crest or sternum, in which a specimen is aspirated using a wide bore needle from the active marrow, smeared, stained and then examined for any abnormalities.2. Bone marrow biopsy : here a core of bone marrow tissue is taken, and processed and stained as in histopathological specimens (H&E stain)