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30 Cards in this Set
- Front
- Back
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Recognize that red blood cells are unusual cells in the body in areas of lifespan, metabolism, nuclear status and physiology.
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Be aware that having normal levels of healthy red blood cells requires nutrients and an effective place of production (bone marrow), a plasma environment free of immune attack against them, and intact blood vessels to contain them (including those in the spleen needed to destroy them when old and dysfunctional).
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Understand the basic schemes and terminologies used to classify anemia, with iron deficiency anemia as an example within those classification schemes.
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erythrocytes
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-RBCs -Structure: 1. anucleate- no DNA 2. no mito- rely on glucose (glycolysis/HMP shunt) as only E source → anaerobic → lactate -d= 7.8 um -Shape: biconcave disc --high SA/V |
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carboxyhemoglobin
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CO poisoned Hb |
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hypoxia
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sources: 1. high altitude 2. chronic lung disease 3. poor cardiac function 4. anemia |
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erythropoietin
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hormone released by kidney in response to low O2 levels in blood → stimulates erythropoiesis in bone marrow by binding to its receptor on stem cells → increased production of proerythroblasts (takes a few days for new RBCs to emerge) -gene activated by hypoxia-inducible factor-1 |
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iron
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-Fe2+ absorbed in SI → plasma and bound by Transferrin → tissues and released as Free iron → stored by Ferritin -Transferrin takes to bone marrow → incorporated into Hb= RBCs |
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carbaminohemoglobin
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CO2 loaded Hb |
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iron deficiency anemia
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microcytic hypochromic anemia (small and very pale on slide) (example of mechanistic and morphologic classification) |
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RBC dysfunction
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anemia: reduction to below normal limits of RBC mass or O2 carrying capacity -majority* polycythemia: excess RBCs |
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bicarbonate
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main transporter of CO2 |
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reticulocyte
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-immature RBC -Reticulocyte Count: 0.5-1.5% (normal) -still contains basophilic material= organelle and RNA remnants -diapedesis -Wright Stain: hard to see but slightly grayish hue -New Methylene Blue Stain = "reticulocyte stain" = "brilliant cresyl blue" (old) → binds the residual RNA still present |
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hematocrit
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-RBC fraction = ~40% -centrifuge blood → RBCs got to bottom, WBCs/platelets middle, plasma to top (~60%) *avg adult blood V= 5 Liters 3 L=plasma 42 L = total Body Water |
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chloride shift
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1. carbonic anhydrase: CO2 + H2O ↔ H2CO3 ↔ HCO3- + H+ -only in RBCs 2. anion exchange protein (Band 3): -on RBC cell membrane -exchanges HCO3- for Cl- |
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diapedesis
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-when cell is reticulocyte passes from marrow through vessel capillary wall into blood capillary -w/n two days loses basophilic material (organelle and RNA remnants) → mature RBC |
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blood type |
-glycoproteins (agglutinogens) determine blood type --don't make Ab to whats on your RBCs (O- is universal donor, AB+ universal acceptor) |
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chloride shift at tissues |
CO2 diffuses into RBC down conc. grad → HCO3- + H+ → HCO3- goes down conc. grad through Band 3 and Cl- comes in; H+ binds Hb → O2 released |
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chloride shift at lungs |
CO2 exits blood to lung → H+ and HCO3- converted to H2O and CO2 → breathe out → decreased pH → O2 binds Hb |
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bone marrow |
-specialized burturing environment for blood stem cells -fetus: liver makes RBCs -< 5 yrs = marrow of all bones makes (esp long bones) -after 20 = RBCs made in torso bone marrow (vertebrae, sternum, ribs) |
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erythrocyte stem cells |
-pluripotential hematopoieitic stem cell: all blood cells trace back to -proerythroblast: first cell in RBC series= stem cells committed to being RBCs |
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eryhtrocyte homeostasis |
decreased RBC → hypoxia → hypoxemia → drop in oxygen supplied to tissues → kidney detects low O2 → upregulates hypoxia-inducible factor-1 (TF) → erythropoietin transcription activated → releases erythropoietin → travels to bone marrow → binds receptor on stem cells → increased production of proerythrobloasts → more RBCs produced → reticulocyte stage does diapedesis → increased O2 carrying ability of blood -total RBC mass regulated --enough to transport O2 well --don't want too much → reduced flow |
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RBCs lifespan and destruction |
120 days (math makes sense for reticulocytes being 0.5-1.5%) -cell membrane becomes fragile → tight/winding/challenging vessels tear membrane → destroyed (Spleen major organ with these vessels) -macrophages ingest debris -heme → bilirubin |
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anemia classification: mechanisms |
1. blood loss -acute (stabbed) -chronic (colon bleed) 2. increased RBC destruction -G6PD deficiency, sickle cell, pyruvate kinase deficiency. hemolytic disease of newborn (Rh disease) 3. decreased RBC production -whole body irradiation, Fe deficiency |
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anemia symptoms |
-fatigue -weakness -pallor -short of breath on exertion -malaise |
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anemia classification: morphological criteria |
(reflects features on microscope) 1. microcytic-small 2. macrocytic-big 3. normocytic-normal 4. hypochromic- pale, less Hb etc. combine size and color: microcytic hypochromic anemia |
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anemia diagnosis |
-CBC -peripheral smear -bone marrow -hematocrit -serum chemistry (other special studies) |
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Complete blood count (CBC) |
-impedence cytometer directly measures: 1. WBC 2. RBC 3. Hgb 4. MCV (Mean Cell V) 5. Platelets -→ calculate: Hematocrit= RBC x MCV (and other thigns) |
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Peripheral smear |
-blood smear? -perfect position is near edge but don't want too thin! (don't want too think.. want just right!) |
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Lab tests in anemia workup |
1. Red Blood Cell Count (RBC): #RBCs/unit V 2. Hematocrit (Hct): V RBCs/ V blood 3. Hemoglobin concentration (Hgb): amount of Hb/V of blood |
