Bone Marrow Flashcards
Detail the phases of hemopoiesis
Mesoblastic phase (2 weeks post conception, Yolk sac)
Hepato-splenic phase (2nd month, Liver and spleen)
Myeloid phase (2nd trimester and throughout life, bone marrow)
Leukocytes appear by 8th week of gestation
What are the two types of hemopoietic tissue in bone?
Bone marrow (myeloid tissue) Lymphoid tissue
Where does hematopoeisis occur post-birth?
Red bone marrow in the medullary cavity of long bones when young. That turns to yellow marrow when older. Can be repopulated to red if need be All red bone marrow is usually in the epiphyses (head) of bone
What is the stroma of bone marrow?
3D network of reticular ad adventital cells and reticular fibers (type III collagen)
Properties of capillaries in the stroma
Sinusoidal formed by continous layer of endothelial cells reinforced by reticular cells and fibers
What is the parenchyma of bone marrow?
Divided into hematopoietic compartments and responsible for the synthesis of erythrocytes and leukocytes
What are megakaryocytes?
Largest cells in bone marrow. Makes platelets
Erythroblastic islets function to?
Make RBC
Fibroblasts function to do what in the bone marrow?
Support the endothelium of the sinus capillaries and also produce the reticular fibers
T or F: Endothelial cells in bone marrow can be darkly stained by a separate stain to H&E
T
What stage of hematopoietic development are morphological differences apparent?
Precursor cells (blasts)
Pluripotent stem cells are made into what two possible cells for hematopoietic asymmetric differentiation?
Lymphoid multipotential cells
Myeloid multipotential cells
Lymphoid multipotential cells do?
Migrate to lymphoid organs and form LCFC (lymphocyte colony forming cell)progenitor cells then lymphoblasts then B and T lymphocytes
What is the process of cell differentiation from pluripotent cells?
Stem cells to progenitor cells to precursor cells (blasts) to mature cells
Describe the morphologic and mitotic characteristics of stem cells
Not morphologically distinct, all have aspect of lymphocytes. Low mitotic activity, self renewing, scarce in bone marrow
Describe the morphologic and mitotic characteristics of progenitor cells
Not distinguishable, have general aspect of lymphocytes, high mitotic activity, self-renewing, common in marrow and lymphoid organs, mono- or bipotential
Describe the morphologic and mitotic characteristics of progenitor cells
Beginning of morphological differentiation, high mitotic activity, not self renewing, common in marrow and lymphoid organs, monopotential
Describe the morphologic and mitotic characteristics of mature cells
Clear morphologic differentiation, no mitotic activity, abundant in blood and hematopoietic organs
Myeloid multipotential cells (stem cell) can be made into what?
Erythrocyte colony forming cells (ECFC), Megakaryocyte forming cell, MGCFC/Monocyte-colony-forming cell/Granulocyte-colony-forming cell, Eosinophil colony forming cell (EoCFC), and Basophil-colong-forming cell BCFC
Trace production of B and T lymphocytes from progenitor cells
Pluripotent to lymphoid multipotential cells (migrate to lymphoid regions) to LCFC to Lymphoblast to B and T lymphocytes
Trace production of Erythrocytes
PP cells to Myeloid multipotential cell in bone marrow to ECFC to Erythroblasts to Erythrocytes
Trace production of megakaryocytes
PP cell to Myeloid multipotential cell in bone marrow to megakaryocyte forming cell to megakaryoblast to megakaryocyte
Trace formation of monocytes
PP cell to Myeloid MP cell in bone marrow to MGCFC to MCFC to promonocyte to monocyte
Trace the formation of neutrophilic/eosinophilic/basophilic granulocytes
PP cell to myeloid MP in bone marrow to -CFC (G,Eo,B) to Neutro/Eosino/Basophilic myelocyte to Neutro/Eosino/Basophilic granulocyte
Pluripotent cells in bone marrow are how abundant?
Very rare <0.1% of nucleated cells in bone marrow
When are growth factors most effective on hematopoetic cells during differentiation?
Between progenitor and precursor cell stage. Growing to that point and decreasing after
Follow Erythropoiesis stages
Proerythroblast to basophilic erythroblast to polychromatophilic erythroblast to orthochromatophilic erythroblast to reticulocyte to erythrocyte
Follow granulopoiesis for neutrophil
Myeloblast to premyelocyte to Early neutrophilic myelocyte to late neutrophilic myelocyte to neutrophilic metamyelocyte to band cell to mature neutrophil
Follow granulopoiesis for eosinophil
Myeloblast to premyelocyte to early eosinophilic myelocyte to late eosinophilic myelocyte to eosinophilic metamyelocyte to mature eosinophil
Follow granulopoiesis for basophil
Myeloblast to premyelocyte to early basophilic myelocyte to late basophilic myelocyte to mature basophil
A proerythroblast leads to how many RBC after erythropoiesis?
8 cells
Properties of proerythroblast
Large, loose lacey chromatin, very visible nuceoli (ribosomes), basophilic cytoplasm
Properties of basophilic erytroblasts
Onset of Hb synthesis, strong basophilic cytoplasm, condensed nucleus no nucleoli
Onset of Hb synthesis occurs at what stage?
Basophilic erythroblast
Properties of polychromatophilic erythroblast
Cytoplasm filled with Hb, polyribosomes begin to decrease, final stage of mitosis possible
What is the last stage of mitotic division possibility for RBC?
Polychromatophilic erythroblast
Properties of orthochromatophilic erythroblasts
Cytoplasm filled with Hb, few polyribosomes, condensed nucleus, sometimes called a normoblast (late orthochromatophilic erythroblast)
Properties of reticulocytes
Anucleate, most immature form released into blood
Length of time for RBC production?
3-5 days. Last for 120 days
How does precursor RBC lose nucleus?
Via pyknotic body that is eaten by macrophage
What is erythropoietin?
cytokine that pushes erythroblast toward RBC differentiation
Properties of myeloblast
Large round nucleus with finely dispersed nucleus, visible nucleoli
Properties of promyelocyte
Basophilic cytoplas and azurophilic granules (lysosomes)
Properties of Myelocyte
Coarse chromatin, neutrophilic,eosinophilic, or basophilic specific granules appear, final stage at which mitosis can occur
When do azurophilic granules form?
Promyelocyte phase
When do specific granules appear in granulopoiesis?
Myelocyte phase
When does mitosis stop in granulopoiesis?
Myelocyte phase
Properties of metamyelocyte
Indented nucleus with coarse chromatin.
N,E, or B specific granules increase in number
Band form properties
Band or Ribbon shaped nucleus
Most immature stage released to circulating blood
Stages of Monopoiesis
Monoblast to Promonocyte to Monocyte
Properties of monoblast
Similar to myeloblast (large round nucleus with dispersed chromatin and visible nucleoli)
Properties of promonocyte
Large cell, basophilic cytoplasm, slightly indented nucleus with lacy chromatin and evident nucleoli, last mitotic stage
Last mitotic stage of monopoiesis
Promonocyte
Location of lymphopoiesis
Circulating lymphocytes originate mainly in thymus and peripheral lymphoid tissue but all lymphocyte progenitors initially come from bone marrow.
Stages of lymphopoiesis
lymphoblast to prolymphocyte to lymphocyte
Properties of lymphoblast
first identifiable progenitor in bone marrow, large cell capable of dividing 2-3 times
Properties of prolymphocyte
Smaller than lymphoblast, more condensed chromatin, lack surface antigens (T&B), migrate to lymphoid tissue to undergo further maturation and become immunocompetent
Two types of leukemia
Chronic and Acute
Properties of chronic leukemia
Slowly progressive, proliferating cells are partly or completely differetiated e.g. myelocytes, metamyelocytes, band cells seen in chronic granulocytic leukemia
Properties of acute leukemia
Rapidly progressive, proliferating cells are undifferentiated precurosors e.g. myeloblasts as in acute myeloblastic leukemia
Stages of platelet formation
Megakaryoblast to Megakaryocyte to Platelets
What is thrombocytopenia?
Severe reduction in number of circulating platelets.
What are the two types of thrombocytopenia purpura?
Petichiea (small dark spots of clotting) and Echymoses (bruise)
T or F: Leukemia, metastatic cancer, and chemo drugs can lead to thrombocytopeneia
T
