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30 Cards in this Set
- Front
- Back
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Hemopoiesis in adults occurs in
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bone marrow; mainly of the skull, ribs, sternum, vertebral column, pelvis and the proximal ends of the femurs
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Development from embryo
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ectodermal cells migrate to yolk sac and become stem cells
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Mesoblastic Phase
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2-5 weeks
Mesenchymal cells aggregate in blood islands |
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Hepatic Phase
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6-11 weeks
cells migrate to liver erythrocytes still have nuclei WBC appear |
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Splenic Phase
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12 weeks-end of gestation
cells migrate to spleen |
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Myeloid Phase
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24th week
Hemopoiesis in bone marrow |
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Pluripotential stem cell
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primitive cell, all blood cells come from
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Unipotential stem cells
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5 types, differentiate into lineages
erythrocytes granulocytes lymphocytes monocytes platelets |
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Colony forming units (CFU)
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progenitor cells
division rate controlled by poietins (hormones), colony stim factors, and interleukins |
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Bone Marrow-structure
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meshwork of vascular sinuses and highly branched fibroblasts
interstices packed with haemopoietic cells |
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Bone Marrow-Function
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blood cell production
removes old erythrocytes immunity-plasma cells and site of B-lymphocyte differentiation |
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Red Marrow
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reticulin framework
marrow stromal cells sinusoids draining to cental vein |
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Bone marrow sinuses
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continuous endothelium
basement membrane is discontinuous endothelial cells control movement in and out of hemopoietic compartment, but very thin cytoplasm for movement of whole cells |
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marrow stromal cells
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cytomplasmic processes, touch outer sinus walls and extend
synthesize reticulin fibers support hemo cells |
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non cellular support
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collagen fibres
proteins laminin and fibronectin;bind the haemopoietic cells to the fibrous elements of the marrow stroma |
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ground substance proteoglycans
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bind growth factors, modulators
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Erythropoiesis steps
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1.Proerythroblast
2.Early normoblast (basophilic erythroblast) 3.Intermed. normoblast (polychromatic erythroblast) 4.Late normoblast (orthochromatic erythroblast) 5.Reticulocyte 6.Erythrocyte |
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Erythropoiesis differentiation
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decreased size, extrude nucleus
loss of organelles increase cytoplasmic hemoglobin |
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Proerythroblast
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Large, light nucleus
basophilic cytoplasm organelles no hemoglobin |
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Early normoblast
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hemoglobin synthesis begins
cell division stops basophilic cytoplasm |
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Intermed. normoblast
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further loss of organelles
more hemoglobin smaller nucleus polychromic cytoplasm |
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Late normoblast
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few organelles
lots of hemoglobin extrude nucleus eosinophilic cytoplasm |
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Reticulocyte
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complete synthesis of hemoglobin
no nucleus few organelles in marrow for a day-->circulation-->erythrocyte |
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Erythropoiesis control
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process-1 week
hormone erythropoietin secreted by the kidney availability of red cell components: iron, folic acid, vitamin B12 and protein precursors |
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Granulopoiesis steps
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1.myeloblast
2. promyelocyte 3. myelocyte 4. metamyelocyte 5. band/stab |
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myeloblast
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round nucleus, uncondensed chromatin
visible nucleolus no granules |
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promyelocyte
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round nucleus, uncondensed chromatin
few oval nucleoli synthesis primary granules (red) basophilic cytoplasm= rER |
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myelocyte
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round/oval nucleus, may be slightly indented
no nucleoli some primary granules, but synthesis of secondary granules last capable of cell division |
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metamyelocyte
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eccentric, bean shaped nucleus
condensed chromatin more specific granules |
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band form
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nucleus U shaped
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