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20 Cards in this Set
- Front
- Back
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name the normal pathway of erythropoeisis
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SC--> GEMML --> GEMM --> MEG/ERY (GATA-1) --> ERY (EPO)
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where is EPO made and what is the role of EPO in erythropoiesis
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EPO is mostly made in kidneys - by interstitial renal tubular cells (10% in liver). it keeps BFU-E and CFU-E from apoptosing further down the maturation timeline (much longer than pathway say for platelets or myeloid cells)
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EPO is released in response to what? (2)
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hypoxemia (low o2) or anemia
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what does renal insufficiency cause?
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normochromic normocytic anemia
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tell me about HIF-1 alpha and EPO
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High o2 levels allows hydroxylation of HIF1-alpha (adding -OH) and subsequent degradation by ubiquitin (via vonHippel Lindau)
low o2 levels decreases the ubuiquitnation and degradation of HIF1-alpha, so that HIF 1-alpha and HIF-1 beta can activate EPO gene for transcipriton of more EPO protein |
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how does the EPO receptor work? how do mutations affect this?
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EPO causes dimerization of EPO-receptor (in a jak/stat pathway)
Mutations in this pathway can allow EPO-R dimerization w/o EPO binding, leading to congenital polycythemia. This is spontaneous polymerization, which greatly increases erythrocyte production!! |
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state the 3 main fxn's of rbc's
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- transport of o2 (as well as scavenger of NO - causing vasodilation)
- hemostasis (increases hemostatic effects of platelets) - clearance of immune complexes |
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why do sickle cell pts have pulmonary HTN?
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their rbc's aren't fxning and NO is less scavenged...leading to vasoconstriction
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how can low affinity Hb lead to polycythemia?
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pts need more RBCs to get the same amt of 02 to their tissues
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on the pressure vs. o2 affinity graph, what are some things that cause a left-shift in the curve? what about right shift?
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left shift (higher affinity for o2): inc pH (ie. being around the lungs rather than acidotic muscles), dec Temp, increased affinity Hb (HbF, being in a higher altitude), dec 2,3-DPG
right shift: dec pH (being around acidotic muscles), inc temp, dec Hb affinity, inc 2,3-DPG |
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how does 2,3-DPG work?
what would happen in an anemic pt? |
shifts the curve to the right and dec the affinity for oxygen, allowing for increased delivery of oxygen to tissues
in an anemic patient, you would need to decrease your 2,3-DPG, so that your affinity of Hb for O2 will be much higher |
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what are the principal Hb's? which is more abundant at birth
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- HbA (adult Hb, most important)
- Hb A2 - Hb F (fetal Hb) at birth, you have mostly HbF. prior to birth, the erythroid elements "switch" to production of HbA |
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why aren't mutations in HbA (thalassemias, sickle cell) noticed until later in birth?
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Mutations (thalassemias, sickle cell) aren’t noticed until 6-9 mo post birth bc baby is protected by residual HbF for first 6-9 mo.
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name the 2 main types of anemias
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proliferative (hemolytic anemias) and hypoproliferative (dec bone marrow production)
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which type of anemia is assoc witih pancytopenia and dec reticulocytes?
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hypoproliferative
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how does 2,3-DPG work?
what would happen in an anemic pt? |
shifts the curve to the right and dec the affinity for oxygen, allowing for increased delivery of oxygen to tissues
in an anemic patient, you would need to decrease your 2,3-DPG, so that your affinity of Hb for O2 will be much higher |
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what are the principal Hb's? which is more abundant at birth
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- HbA (adult Hb, most important)
- Hb A2 - Hb F (fetal Hb) at birth, you have mostly HbF. prior to birth, the erythroid elements "switch" to production of HbA |
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why aren't mutations in HbA (thalassemias, sickle cell) noticed until later in birth?
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Mutations (thalassemias, sickle cell) aren’t noticed until 6-9 mo post birth bc baby is protected by residual HbF for first 6-9 mo.
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name the 2 main types of anemias
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proliferative (hemolytic anemias) and hypoproliferative (dec bone marrow production)
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which type of anemia is assoc witih pancytopenia and dec reticulocytes?
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hypoproliferative
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