Card Set Information
In embryo and fetus, hematopoiesis takes place first in _______, progressing to......
Blood islands in yolk sac; then liver and spleen, then the bone marrow and lymphoid tissue.
In adult mammals, hematopoiesis occurs in...
Bone marrow (primarily)
When hematopoiesis takes place in the liver and spleen due to pathological conditions.
Extramedullary hematopoiesis (EMH)
Three things required for normal hematopoiesis.
HSC, cytokines, BM microenvironment
Three capabilities of hematopoietic stem cells.
self-renewal, division, and differentiation
Hematopoietic stem cells can be purified based on...
expression of surface proteins (ex. CD34)
HSC are present in _____ in normal bone marrow.
low numbers (<0.01%)
HSC differentiate into....
common myeloid or common lymphoid progenitors
Hematopoietic tissue consists of (3)...
hematopoietic cells, stromal tissue, and vascular sinuses lined by endothelium.
In mammals, hematopoiesis occurs within _____.
extravascular spaces in BM
What are the components collectively known as the BM microenvironment or stroma? (6)
reticulocytes, adipocytes, endothelial cells, myoytes, nerves, and the extracellular matrix
extracellular matrix includes... (3)
collagen, laminin, fibronectin, and other macromolecules important in cell binding
(4) ________ important in hematopoiesis because they help create niches for cell maturation.
macrophages, lymphocytes, osteoblasts, and NK cells
Active BM is _____, and inactive BM is _____.
Red(hemoglobin in erythroid precursors); yellow (adipose tissue)
HSC --> common myeloid progenitor--> rubriblast --> prorubricyte --> rubricyte --> metarubricyte --> polychromatophilic RBC --> mature RBC
Describe the location of erythropoiesis.
erythroid island- central macrophage is surrounded by 10-30 erythroid cells (various stages)
RBC maturation is characterized by... (5)
decreasing cell size, decreasing nuclear size and eventual extrusion (thus chromatin condensation), and decreasing cytoplasmic basophilia (loss of ribosomes, gain hemoglobin)
What is the final erythroid precursor that still has a nucleus?
metarubricyte (nucleus is extruded, becoming polychromatophilic RBC)
erythroid precursor with prominent nucleolus, deeply basophilic (blue) cytoplasm, and fine chromatin
erythroid precursor with slightly clumped chromatin, no nucleolus, and less basophilic cytoplasm (hemoglobin synthesis has begun)
erythroid precursor with highly condensed chromatin, and less basophilic cytoplasm (hemoglobin synthesis has continued)
erythroid precursor with a pyknotic nucleus, red cytoplasm, and does not circulate in health
non-nucleated erythroid precursors that circulate in low numbers in healthy individuals; does not contain as much hemoglobin as a mature RBC
polychromatophilic RBC vs. reticulocyte
polychromatophilic RBC has been stained with wright's stain (routine); when stained with NMB, ribosomes and organelles condense to blue meshwork, and cell is known as reticulocyte
Erythropoietin (EPO) is a _____ produced primarily by ____ in the _____ in response to ____.
glycoprotein; peritubular interstitial fibroblasts; renal cortex; tissue hypoxia;
Purposes of EPO (5)
stimulate HSC commitment to erythroid lineage, prevent apoptosis of erythroid precursors, reduces BM transit time (shortens G1 phase), increases hemoglobin synthesis, indues the release of polychromatophilic circulation [[[regenerative anemia]]]
hormones that stimulate erythropoiesis (6)
EPO, androgens, glucocorticoid hormones, growth hormone, insulin-like growth factors, and thyroxine
inhibitors of erythropoiesis (4)
estrogen, TNFα,β, γ interferon, and IL-6
HSC--> common myeloid progenitor --> myeloblast --> promyelocyte (progranulocyte) --> myelocyte I--> myelocyte II --> metamyelocyte --> band cell --> segmented cell --> neutrophils, eosinophils, basophils
Granulocyte maturation is characterized by... (4)
decreasing cell size, condensation of chromatin, progressive nuclear indentation and segmentation, and formation of granules
granulocyte precursor with fine chromatin, 1-3 nucleoli, basophilic cytoplasm (lighter than rubriblast), and no granules.
granulocyte precursor with central or eccentric round nucleus, fine chromatin, inconspicuous nucleoli, and abundant basophilic cytoplasm with azurophilic granules.
granulocyte precursor with an eccentric round or oval nucleus, beginning condensation of chromatin, and light blue cytoplasm with specific granules.
granulocyte precursor with an indented, bean-shaped nucleus, clumped chromatin, slightly basophilic or clear cytoplasm, and specific granules; non-mitotic (maturation and storage pool).
granulocyte precursor with a nucleus with parallel sides (horseshoe or S), a smooth nuclear membrane, and specific neutrophilic granules.
granulocyte precursor with an irregular nuclear membrane with constrictions that for 2-5 lobes.
which granulocyte precursors are in the proliferating pool (undergoing mitosis and differentiation)?
myeloblasts, progranulocytes, and myelocytes
which granulocyte precursors are in the storage and maturation pool (non-dividing)?
metamyelocytes,bands, and segmented cells
cytokines and growth factors for granulopoiesis (7)
SCF, IL-3, IL-5, IL-6, GM-SCF, G-CSF, and glycoproteins produced by monocyte, fibroblassts, endothelial cells, and lymphocytes
common lymphoid progenitor --> small lymphocyte --> B cell --> plasma cell
NK cell T cell
HSC --> common myeoid progenitor --> megakaryoblasts --> promegakaryocytes --> megakaryocytes --> platelets
During thrombopoiesis, ______ causes progressive increase in ploidy.
endomitosis (nuclear duplication without cell division)
megakaryoblast cytoplasm vs megakaryocyte cytoplasm
megakaryoblasts have basophilic, agranular cyoplasm; megakaryocytes have numerous granules, which contain growth factors, chemokines, clotting proteins, and adhesion molecules
in mammal, platelets are partitioned off from _____ that protrude into ______.
proplatelet processes; the lumen of the sinuses
major ytokine involved in platelet production