Origin, Development and Anatomy of Blood and Blood-forming Organs
Terms
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Types of Hematopoiesis
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- Medullary Hematopoiesis: Bone Marrow
- Extramedullary hematopoiesis: Outside of the marrow. Also made in the liver and spleen
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Hematopoiesis in the Embryo and Fetus
- Mesoblastic period: yolk sac
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- Mesenchyme cells: undifferentiated precursor of all tissues. Give rise to fat, cartiledge, bone.
- Blood island surrounded by endothelial cells
- Blood cells (free) in lumen of primiti
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Hematopoiesis in the Embryo and Fetus
2. Hepatic Period: Liver and spleen
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Liver and spleen starts to differentiate to lymphocytes.
- Liver 80%
- spleen 20%
- Liver 80%
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Hematopoiesis in the Embryo and Fetus
3. Myeloid period: bone marrow
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- Gone into the bone and start to make blood
- monocytes and megakarocyte
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Skeletal:
- Axial
- Appendicular
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- Adult (top of humerus, femur, peliv,sternum, cranium, vertebral skeletal always making blood)
- PSIC
- ASIC, spinal processes or vertebral bodies
- Sternum
- 1-2 ml bone marrow aspirated
- Adult (top of humerus, femur, peliv,sternum, cranium, vertebral skeletal always making blood)
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Types:
- Red Bone Marrow
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- Actively producing RBC, WBC, platelets
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Types:
- Yellow Bone marrow
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- Full of fat
- In emergencies fat can change to RBC
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Anatomy of Bone
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- Cancellous: spongy bone "trabeculae"
- hematopoietic cord
- marrow sinus "space"
- central vein
- Granulocyte, megakaryocyte,and erythroblast seen
- Cancellous: spongy bone "trabeculae"
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Indications for Bone Marrow Studies:
- Primary hematologic disease
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- Anemia, erthrocytosis, polycythemia
- Leukopenia & leukocytosis
- Immature of abnormal cells in circulation
- Thrombocytopenia & thrombocytosis
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Indications for Bone Marrow Studies:
- Secondary hematologic disease
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- Solid malignant tumors that metastasize to bone marrow (i.e. Ovarian, lung cancer)
- Disseminated bacterial, fungal, or protozoan infections
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Bone marrow aspirate examination:
1. Estimation of cellularity
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- Red bone marrow (RBC, WBC, and thrombocyte precursors) vs. yellow bone marrow (fat cells); normally 50% red marrow in adult
- Myeloid: Erythroid (M:E ratio)
- ratio of WBC precursors and mature WBC vs. RBC precursors
- M:E ra
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Bone marrow aspirate examination:
2. Differential nucleated cell count
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- bone marrow is prepared for examination
- coverslip and slide prep are stained to differentiate types of formed elements
- 1000 nucleated cells (WBC & RBC) are counted
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Nucleated Cell differential and reporting
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- Pronormoblasts 0-1.5
- Basophilic nomoblasts 0-5
- Polychromatophilic normoblast 5-30
- Orthochromatic normoblasts 5-10
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Bone marrow aspirate examination:
3. Iron stores and special stains -
- Wright Giemsa
- Wright Giemsa
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Reticuloendothelial System (RE)
(mononuclear, phagocytic)
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- fixed macrophages: tissue cells (spleen)
- free macrophages: connective tissue
- endothelial cells
- circulating monocytes: in the blood stream, leave in 12 hrs and become macrophages