Question | Answer |
What does an erythropoetic progenitor cell compartment represent? | A unipotential cell committed to differentiate into erythroid cells only |
What does a cell require to commit to becoming an erythrocyte? | Erythropoietin |
What are the 2 progenitor cells in erythropoiesis? | BFU-E and CFU-E |
BFU-E stands for what? | Burst forming unit - erythroid |
What does CFU-E stand for? | Colony forming unit - erythroid |
What progenitor cell represents the most primitive erythroid progenitor cell? | BFU-E |
Which erythroid progenitor cell is more sensitive to erythropoietin? | CFU-E |
What acts in synergistic action on EPO to induce proliferation and differentiation of a CFU-E? | IL-3 and GM-CSF |
CFU-E is a precursor to what? | Pronormoblast |
What is the first precursor cell to be morphologically distinguished as a forming RBC? | Pronormoblast |
A RBC grows (smaller or larger) as it matures? | Smaller |
As a RBC grows, nuclear chromatin (expands or condenses)? | Condenses as heterochromatin |
What are the 5 stages of maturation before a RBC becomes a mature erythrocyte? | 1. Pronormoblast
2. Basophilic normoblast
3. Polychromatophilic normoblast
4. Orthochromatic normoblast
5. Polychromatophilic erythrocyte |
Each pronormoblast gives rise to a potential of how many mature RBC? | 16 |
How long does the maturation process in the bone marrow take? | 5 to 7 days |
Polychromatophil erythrocytes circulate for approximately how long before maturation is completed? | 24 -48 hours |
What is the life cycle of a mature RBC? | 120 days |
What happens to senescent erythrocytes? | They are removed from circulation by splenic macrophage phagocytosis. |
Erythropoietin hormone comes from what gland? | The endocrine gland |
Where is erythropoietin synthesized? | The kidney |
Erythropoietin is released from the kidney in response to (increased or decreased) oxygen tension? | Decreased |
A cell must possess what in order to respond to EPO? | An EPO receptor |
Which developing stage of erythropoiesis does not have an EPO receptor? | Polychromatophillic erythrocyte |
What 3 growth factors play a role in erythropoiesis? | Erythropoietin, IL-3, and GM-CSF |
What does GM-CSF stand for? | Granulocyte/monocyte colony stimulating factor |
What is IL-3 produced by? | Activated T-cells (TH1 & TH2) |
GM-CSF is produced by ______ & _______? | T-cells and endothelial cells |
GM-CSF promotes (proliferation or differentiation) in the presence of (EPO or IL-3) | Proliferation; EPO |
The rate of erythropoiesis is governed by what? | The rate of oxygen transport to the tissues |
What 4 things does oxygen transport to the tissues depend on? | 1. Concentration of hemoglobin in the blood
2. Cardiac output
3. Oxygen saturation of hemoglobin
4. Hemoglobin's affinity of oxygen |
EPO production is affected by what 4 hormones? | 1. Testosterone
2. Glucocorticoids
3. Thyroxine
4. Growth hormone |
The hormones which affect EPO production have a direct or indirect relationship with EPO? | Direct |
What is effective erythropoiesis? How do we measure this? | A representation of the number of viable, functional RBC's available; reticulocyte count |
What is total erythropoiesis? How is it measured? | A representation of erythroid precursors in the bone marrow; myeloid:erythroid ratio as well as bone marrow cellularity |
What is a normal myeloid:erythroid ratio? | 3:1 |
How do we measure ineffective erythropoiesis? | Total erythropoiesis - effective erythropoiese |
As a mature RBC, the nucleus contracts as chromatin condenses into a functionless _________ which is finally extruded. | pyknotic mass |
Does a mature RBC contain protein synthesizing organelles and mitochondria? | No |
The stage of erythrocyte accumulates a full complement of hemoglobin. | A mature erythrocyte |