Term
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Definition
Transient, primitive program
Begins in early embryogenesis
First 8 weeks: cells arise in the embryonic yolk sac |
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Term
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Definition
What we see in the adult
Begins during fetal life in association with vascular structures (fetal aorta, placenta)
Expands in the fetal liver and spleen
In the late fetus the bone marrow becomes the main site of hematopoiesis |
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Term
| Shifting Sites of Human Hematopoiesis |
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Definition
| yolk sac until 3 mos, then liver/spleen peak at 5 months, BM/axial skeleton and lesser degree distal long bones peak at 8-9 mos and decrease. |
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Term
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Definition
| numbers are low, can’t be detected through microscopy, ID relies on cell surface markers, specifically CD34, in addition to Thy-1la and c-Kit |
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Term
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Definition
| from aorto-gonadic mesonephric region (AGM) in the ventral aspect of the dorsal aorta => hemangioblast => hematopoietic stem cells |
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Term
| Stem Cell differentiate how? |
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Definition
• Transcription Factors – balance of various TFs predisposes stem cells to differentiate in various ways
• Growth Factors – from bone marrow environment, interact with cells at different stages to promote cell growth
o Early development – cells stay near cytokine-rich bony spicules, receive many growth factors
o Late development – cells migrate into sinuses, become mature & ready for use |
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Term
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Definition
o Common Lymphoid Precursor (CLP) – makes B & T lymphocytes, NK cells
o Common Myeloid Precursor (CMP) – makes various myeloid precursors:
Granulocyte precursor – gives rise to neutrophils, eosinophils, basophils
Monocyte precursor – can mature into macrophages
Erythroid/megakaryocyte precursors – mature into RBCs, platelets |
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Term
| Hemoglobin req what for synthesis |
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Definition
| major protein component of RBCs, requiring globins, protoporphyrin, & iron for synthesis |
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Term
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Definition
• Process: HSCCMPBFUCFU Proerythroblast basophilic polychrom ortho retic RBC
o Proerythoblast – small amount of hemoglobin in RBC
o Basophilic erythroblast – more condensed chromatin, more hemoglobin
o Polychromatophilic erythroblast – maximum hemoglobin produced, nucleus condenses
o Orthochromatophlic erythroblast – nucleus fully condensed
o Reticulocyte – nucleus of RBC is extruded, some RNA remains
o RBC – |
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Term
| what signals BFU/CFU differentiation |
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Definition
| • GM-CSF – granulocyte-macrophage colony stimulating factor, cytokine for BFU/CFU diff |
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Term
| Hgb formation as age progresses (1-2 fetal mo, 2-10 fetal mo, newborn/adult) |
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Definition
• ζ,ε – hemoglobin heterodimer present in early embryogenesis (1-2 months)
• α,γ – fetal hemoglobin present in later fetal development (2-10 months)
• α,β – adult hemoglobin (newborn onwards) |
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Term
| What's unique about platelet generation? |
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Definition
Endomitosis – nucleus divides, but cell doesn’t; leads to single polypoid nucleus, hi cytoplasmic volume
Platelet formation – mature megakaryocyte sheds off platelets without nuclei |
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Term
| Key trigger to shed platelets into bloodstream? |
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Definition
| • Thrombopoietin (TPO), IL-11 – play important role in megakaryocyte development – shed platelets into bloodstream |
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Term
| G-CSF is key cytokine to trigger what cell diffx? |
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Definition
PMNs, o Basophils & eosinophils – have common precursor cell before undergoing final commitment
o Mast cells – similar to basophils, derived from HSC developing in tissue |
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Term
| Lymphopoeisis location of maturation |
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Definition
o T-lymphocytes – takes place in thymus
o B-lymphocytes, NK Cells – takes place in bone marrow, then secondary lymph tissue (nodes, spleen) |
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Term
| process of b-cell development |
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Definition
| HSC=>CLP=>Pro/Pre-B => mature B-cell => activation, plasma cell |
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Term
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Definition
| HSC=>CLP=>thymus, differentiate into αβ, γδ lineages *gamma into periphery…* |
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Term
| interleukins key in t-cell development |
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Definition
| IL-7 important early, later IL-1, IL-2, IL-4 |
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