Hematopoiesis Flashcards
What is the receptor responsible for binding growth factors to promote differentiate in hematopoiesis?
Jak-Stat Pathway
What is the growth factors the is responsible for promotion of RBCs and where is it located?
Erythropoietin, Kidney makes 85%+
What is the role of HIF in production of erythropoietin?
HIF-1a in the presence of oxygen is hydroxylated and bound by other co-factors leading to ubiquitation-degradation.
However, when there is hypoxia less hydroxylation occurs and HIF-1a is free to bind in the nucleus as a transcription factor for increased erythropoietin.
(Hypoxia-inducible Factor)
What are therapeutic drugs and when are they used to increase RBC production?
Epoetin Alfa / Darbopoietin
- Chronic Kidney Disease, Post-Chemo, Myelodysplastic Syndrome, etc.
What is the growth factor used to promote the production of megakaryocytes?
Thrombopoietin (TPO)
– Constantly produced within the liver–
How are the levels of platelets regulated with TPO?
Circulating TPO binds to BOTH platelets and megakaryocytes, so if there are few platelets MORE binding to Megakaryoctes, if many platelets, then Less binding to Megakaryocytes reducing proliferation.
What growth factor is used to increase myelocytes?
G-CSF Growth, colony stimulating factor
What produces G-CSF?
Monocytes/Macro, Fibroblasts, and Endothelial cells in order to produce more neutraphils.
What is the therapeutic agent used to increase neutrophils?
Filgrastim.
When needed to prevent infection in compromised patients in chemo, HIV, etc.
What are the cellular markers for a Hematopoetic stem cell?
+c-KIT (CD117)
+CD34
—No lineage specific markers–
What cells do not have CD45?
Erythrocytes and Megakaryocytes
What is the marker on most differentiated cells?
CD45
What are the categorical factors used to be able to tell morphology of cell lineages?
- Cell Size
- Nuclei Shape
- Color of Cytoplasm (Blue, RNA / Red, protein)
- Granules or not
What is a unique characteristic of eosinophils?
Bilobed Nuclei with red-ish granules
What are unique characteristics of lymphocytes?
Smaller in size compared to granulocytes, dark appearing nuclei with a thin layer of cytoplasm.
What are histologic characteristics of proerythroblasts?
Large Size
Blue Cytoplasm
Prominent Nucleolus
What phase of erythrocyte differentiation is smaller than proerythroblast, condensed nucleus that is smaller?
Polychromatophilic Erythroblast – nucleus is more loose
Orthochromatophilic Erythroblast – nucleus is smaller and more dense about to eject
How can you tell the difference between reticulocytes and matured RBCs?
There will be several small blue areas of residual nucleus inside the cell. These will be released into blood and mature completely in 24-48 hours.
How is a myeloblast in histology different than any other of the stages?
There is a prominent nucleolus and not granules.
How are promyelocyte and myeloblast different?
Heavily granulated. Still remains to have a prominent nucleolus.
How can you tell the different between promyelocyte and myelocyte?
Less prominent Nucleolus (or not present)
Cytoplasm is less blue, but still has numerous granules.
What is a distinguishing characteristic of metamyelocyte?
Slightly smaller than less differentiated and has a “kidney shaped” nucleus.
How are metamyelocytes and band cells different?
Band cells have MORE bend, greater than 50% of the thickeness of the nucleus. Horseshoe.
What do matured neutrophils look like?
Multiple lobed usually 3-5 seperated by a thin filament.
