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31 Cards in this Set
- Front
- Back
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Sources of blood in bone marrow circulation |
Nutrient artery Periosteal branch of muscular artery |
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What is the site of hematopoiesis in the bone marrow? |
Hematopoietic inductive microenvironment |
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Cells lining the abluminal surface |
Reticulum cell Macrophages Fibroblast Adipocyte |
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Functions of abluminal surface cells
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-Reticulum cell synthesis & secrete the reticulin fiber - fibroblast secrete collagen fibers - secrete glycoaminoglycan -Reticulin fibres and collagen fibers expresses receptors that are able to interact with early differentiating antigen on hematopoietic cells.This retains the early stage within the HIM - cement tissue help concentrate hematopoietic growth factors |
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What are the cells that gives form to hematopoietic inductive microenvironment? |
Glycoaminoglycan/ cement tissue Reticulate fibers Collagen |
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Example of early differentiating antigen |
CD7 |
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Example of hematopoietic growth factor |
- Erythropoietin - Thrombopoietin -Granulocyte macrophage colony stimulating factor - Granulocyte colony stimulating factor - stem cell factor |
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List the site of hematopoiesis |
- 0-2 months yolk sac 2-8 month - spleen 2month- near term : liver Increase activity of bone marrow at 10- 12 weeks of fetal life shows increase amount of bone marrow First two years of life- bone marrow of all bones Adult- vertebrae, ribs, sternum, skull, sacrum and pelvis, proximal end of femur |
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What are stem cells? |
They have the ability of self renewal and differentiation |
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What are precursor cells? |
They are cells in the bone marrow that can be morphological identified |
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What are progenitor cells? |
They are not morphological identified and are committed to becoming a given cell |
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Most primitive hematopoietic cell |
Pluripotential stem cell |
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Most primitive hematopoietic cell |
Pluripotential stem cell |
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Cells found at the core of the hematopoietic inductive microenvironment |
Lymphopoiesis island |
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Cells found closest to abluminal surface of hematopoietic inductive microenvironment |
Erythropoiesis and thrombopoietic island |
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Morphology of proerythroblast |
-Large cell -Large nucleus -Coin circular nucleus(most important morphological identity) -Thin rim of cytoplasm which is dark blue in color with no evidence of hemoglobin unless tested by feugen tests which reveals scanty hemoglobin -membrane test positive for ABO blood group antigen |
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Red cell stem cell pool include |
Pluripotential stem cell GEMM stem cell |
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Red cell progenitor |
Burst form unit erythroid Colony forming unit erythroid |
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Characteristic of polychromatic erythroblast |
-When stained with romanowski dye, hemoglobin stains red and due to presence of ribosomes it stains blue giving a pink end color. Giving the name polychrome. - larger cytoplasm -Reduced nucleus |
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Characteristics of orthochromatic erythroblast |
-Perfect circular nucleus -cytoplasm is nearly 100% hemoglobinized -nucleus has become solidified and cannot undergo mitosis. - it can only mature by removal of nucleus (enucleation) |
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Explain the concept of macrocyte |
Impaired DNA synthesis, less mitotic stage, this will result in bigger cell |
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Explain the concept of megalobast |
Impaired DNA synthesis, abnormalities in maturation of nucleus( shrinkage) , the cell is dividing but nucleus is not dividing. The nucleus can still carry out transcription to form hemoglobin by translation such condition is nuclear cytoplasmic asynchrony seen in megaloblast |
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Explain the concept of microcytosis |
During hemoglobin acquisition, transcription of corresponding RNA for hemoglobin subunit is required but if any genome for any subunit is deficient. They will be unavailability of hemoglobin and this will result in maturation of nucleus but cytoplasm is not maturing. The compensatory mechanism is increased mitosis resulting in smaller size. |
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Characteristic of reticulocytes |
-Contain remnant of cytoplasmic ribosomes and incompletely extruded nuclear material - when stained with romanowski dye, it shows large quantity if hemoglobin and slight blueish coloration therefor e it is referred to as polychromatic erythrocytes- it is capable of moving out of hematopoietic inductive microenvironment because it has lost its early detection antigen
- it is capable of moving out of hematopoietic inductive microenvironment because it has lost its early detection antigen
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Explain the maturation process of reticulocyte |
-Reticulocyte pass through the endothelial cells of hematopoietic inductive microenvironment into circulation through medullary and emissary vein because it has lost its early detection antigen . - reticulocyte circular to spleen where final maturation occur by removal of ribosomes and fragment nucleus. This process is called the cupping function of spleen |
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Time for polychromatic cell to mature to orthchromatic cell |
5 days |
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Time for reticulocyte to mature to erythrocytes |
2 days |
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Summary of erythropoiesis |
Pluripotential stem cell- myeloid committed stem cell- burst form unit erythrocytes- colony form unit erythrocytes- proerythroblast- basophilic erythroblast type 1- basophilic erythroblast type 2- polychromatic erythroblast- orthochromatic erythroblast- reticulocyte- erythrocytes |
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Summarize the process of platelet formation |
Pluripotential stem cell- myeloid committed stem cell- burst forming unit megakaryocyte- colony forming unit megakaryocyte- megakaryoblast- megakaryocyte |
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Megakaryocyte matures by |
endomitotic synchronous replication |
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Megakaryocyte matures by |
endomitotic synchronous replication |
