lecture 13 Flashcards
What are characteristics of stem cells
proliferate well
self renewing
Reconsisute tissue after injury
What does totipotent mean?
Cell give rise to all cells in organism
ex: Zygote
What is pluripotent?
“Embroyonic Steam cell”
Gives rise to all cells of the embroyo and subsequently and adult tissue
What is multipotent?
Gives rise to different cell types of a given lineage and stem cells
When are hemopoitetic sites?
- 2wks-8wks of gestation
- islands of hematopoiesis (blood islands) are found in yolk sac wall
- First occurance of blood cells
- no leukocytes
- 8wks to 28wks of gestation
- hematopoesis on liver then spleen
- normally ceases around time of birth
- 6 months gestation and beyond
- hematopoesis at read bone marrow
what are characteristics of bone marrow?
- Red marrow is the source of all blood cells
- (at birth all marrow is red marrow)
- Prior to puberty found in
- skull, ribs,, sternum, clavicles, pelvis, long bones
- After puberty
- All of the above except long bones
What extramedullary hemaotpoesis?
blood formation in spleen and liver during certain diease states
What is the stroma ?
- Bone marrow histology
- contains fbroblasts, retictular cells, adipose cells, and endothelial cells
- synthesiss and secreation of hemopoeitic growth factor
What is parenchyma?
consists of various lineges of hematopoetic cells in different stages of differentation
What are sinusoids?
Bone marrow histology
Endothelial lined spaces that connect arterial and venous vessels
provides acess for mature blood cells to move into circulation
what are hematopoietic chords
Bands of parenchyma and stroma lying between sinusoids
know thsi slide
How do RBCs and Megakaryocytes relate to trans endothelial migration?
Mature RBC migrate through hemapotetic cords through sinusodial endothelial walls into the sinusoids
Megakaryocytes (site of platelet production) is too large to translocate and remains in the stroma
memorize and known this slide in and out
What is a hematopotetic cells?
pluripotent
self renews
produce two kinds of multopotent precursors cells
myeloid stem. -> all blood lines EXCEPT lympocytes
lymphoid stem cell - gives rise to lymphocytes
What does a myeloid stem cell form?
- erythoid CFU
- myeloid stem cell -> RBC
- Megakaryocyte CFU
- myeloid stem cell -> platelet precursors
- Basophil CFU *
- Eosinophil CFU *
- Granulocytes CFU *
* = white blood cell
CFU = colony forming units
What does a lymphoid cell form?
T cell progenitor
B cell progenitor
what is the series for granulocyte CFU?
monoblast*
Promonocytes
Monocyte**
macrophage
** = cells normally found in circulation
* = cells which can divide
What is the series for a macrophage CFU?
- Myeloblast *
- Promyelocyte *
- MyeloCyte *
- Metamyelocyte
- Band Cell **
- Neutrophil **
* = cells which can divide
** = normally found in circulation
what is the series for Eosinophil CFU?
- Myeleoblast*
- Promyelocyte*
- Myelocyte*
- Metamyelocyte
- Band Cell**
- Eosinophil or basophil becomes mast cell
* Cells which can divide
** Cells normally found in the circulation
What is the series for megakaryocyte CFU?
- Megakaryoblast
- Mega karyocyte
- Platelets**
* Cells which can divide
** Cells normally found in the circulation
what is the series for Erythroid CFU?
Proerythrobast*
basophillic erythoblast*
polychromatophillic erythroblast
orthochromatic erythroblast
Reticulocyte**
Erythrocyte**
What are the three major hemipoietic growth factors?
Colony –stimulating factors •
Erythropoietin and thrombopoietin •
Cytokines (primarily interleukins)
Where are hemopoetic growth factors and cytokines produced?
endothelial cells in marrow, fibroblasts, and stromal cells
What are colony stimulating growth factors?
granulocyte/monocyte colony stimulating factor (GM CSF)
- Produced by endothelial cells, T cells, fibroblasts, and monocytes
- Stimulates granulocytopoiesis and monocytopoiesis
- Ameliorates neutropenia (synthetic form: sargramostim or melgramostim).
Granulocyte colony stimulating factor (G-CSF):
- Produced by endothelial cells, fibroblasts, and macrophages
- Directs CFU-G to proliferate and differentiate into myeloblasts
- USed after chemotherapy or radiation therapy to treat neutropenia
Monocyte colony stimulating factor:
- Commits CFU-GM to monocytic pathway
What are erythopoeitin and thrombopotein hematopoietic growthf actors?
Erythropoietin:
- Directs CFU-E to proliferate and differentiate into proerythroblasts
- Produced in kidney in response to decrease in oxygen saturation
- Secondary polycythemia is any abnormal increase in total RBC mass resulting from hypoxia and stimulating release of erythropoietin.
- Possible causes include Tetralogy of Fallot and cigarette smoke.
Thrombopoietin:
- Directs formation of megakaryoblasts
- Produced in proximal convoluted tubules of kidney
- Produced in parenchymal cells and sinusoidal endothelial cells of liver
- No therapeutic use
What are Cytokines ?
- Mediate positive and negative effects on cellular quiescence, apoptosis, proliferation, and differentiation.
- Engage specific receptors and activate a variety of signaling pathways.
- Examples:
- Interleukin-3
- GM-CSF
- Fit-3 ligand
- Kit ligand
What are other hemopoeitc growth factors?
ECM components:
- Heparin sulfates
- Collagens
- Laminin
- Fibronectin
Chemokines:
- Regulate blood cell trafficking and homing to sites of need.
- May serve as positive and negative growth regulators. Bind to guanine protein-coupled transmembrane receptors.
- Example: Sdf-1
