Term
| Stages of erythrocyte maturation |
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Definition
| hematopoietic stem cell (HSC) --> common myeloid precursor cell (CMP) --> colony forming unit (CFU-EMk) --> burst forming unit (BFU-E) --> colony forming unit (CFU-E) |
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Term
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Definition
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Term
| maturation process of reticulocyte |
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Definition
| After cell extrudes nucleus it has an odd shape so it is remodeled to eliminate excess membrane and acquire biconcave disc shape. It is alive for 2-3 days and spends half of that time in the bone marrow and half in the peripheral blood |
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Term
| Normal Range for reticulocytes |
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Definition
| percentage in peripheral blood is 0.5-2.5% |
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Term
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Definition
| major cytokine for terminal RBC production |
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Term
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Definition
| Levels increase when hemoglobin levels drop, secreted in response to cellular hypoxia, constant when hemoglobin levels are normal |
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Term
| origin of production of EPO |
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Definition
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Term
| EPO effects on bone marrow |
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Definition
| stimulates the production of RBC from stem cells, allows for more oxygen to be delivered to tissues |
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Term
| erythrocyte membrane functions |
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Definition
| maintain deformability (biconcave shape), elastic extension capability (resume to normal state after being stretched) and permeability (permeable to water and anions, impermeable to cations) |
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Term
| Energy Substrate of the erythrocyte |
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Definition
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Term
| Extravascular erythrocyte destruction |
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Definition
| hemoglobin is broken down in macrophages (spleen, liver and BM) into (1) iron (2) heme and (3) globin. Iron and globin are recycled and heme is catabolized by the macrophages |
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Term
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Definition
Porphyrin ring is cleaved which releases CO (expired) and biliverdin.
Biliverdin is reduced to bilirubin released and bound to albumin, carried to liver and excreted in bile or later in urine |
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Term
| Average dimensions of an erythrocyte |
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Definition
| 8 um in diameter, 2 um thick at the edges, 1 um thick in the middle (biconcave) |
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Term
| life span of an erythrocyte |
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Definition
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Term
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Definition
| produced in the Rapoport-Leubering Shunt via one ATP molecule and is bound by hemoglobin |
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Term
| relationship of 2,3-BPG and erythrocyte |
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Definition
| when hemoglobin binds 2,3-BPG it has a decreased affinity for oxygen and oxygen is released in the tissues |
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Term
| Regulation of Erythrocyte production |
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Definition
| increase in EPO occurs when (1) oxygen delivery to the tissues is impaired (2) low intracellar oxygen |
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Term
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Definition
| due to biconcave shape, stabilizes the viscosity of internal contents of the erythrocyte |
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Term
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Definition
| freely permeable to water and ions, impearmable to cations. Osmotic equilibrium maintained by low permeability to cations, cation pumps and membrane pumps |
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Term
| Mechanisms to regulate permeability to cations |
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Definition
| maintained internally which is different than in the plasma via cation pumps in the membrane (1) Na+/K+ pump and Ca2+ pump |
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Term
| mechanisms to regulate permeability to anions |
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Definition
| the permeability to anions is maintained by the continual uptake of K+ |
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Term
| mechanisms to regulate permeability to glucose |
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Definition
| passive glucose transporter |
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Term
| mechanisms to regulate permeability to water |
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Definition
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Term
| four pathways of erythrocyte metabolism |
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Definition
| (1) glycolysis (2) hexose-monophosphate shunt(3) methemoglobin reductase pathway and (4) rapoport leubering shunt |
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Term
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Definition
| erythrocyte obtains energy in the form of ATP from glucose breakdown |
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Term
| Hexose Monophosphate Shunt (HMS) |
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Definition
| maintains reduced glutathione (GSH) which keeps hemoglobin in its reduced funtional state |
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Term
| Methemoglobin Reductase Pathway |
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Definition
| maintains heme iron in the reduced state by reducing MetHemoglobin back to hemoglobin after oxygen dissociates |
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Term
| Rapoport- Leubering Shunt |
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Definition
| allows for production of 2,3-BPG |
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Term
| Key intermediates of the glycolytic pathway |
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Definition
| glucose is metabolized to lactate or pyruvate (recycled), the cell gains 2 ATPs (maintains shape, flexibility, membrane integrity and normal cation levels) |
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Term
| key intermediates of the hexose monophosphate shunt |
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Definition
| generates NADH, maintains reduced glutathione (GSH)(protects cell from oxidative injury by reducing reactive oxygen species) |
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Term
| key intermediates of the methemoglobin reductase pathway |
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Definition
| maintains iron in ferrous, reduced state, methemoglobin (hemoglobin with iron in ferric state), MetHb reductase and NADH reduce ferric back to ferrous |
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Term
| key intermediates of the rapoport-leubering shunt |
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Definition
| BPG mutase catalyzes 1,3-BPG to 2,3-BPG |
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Term
| Glycolytis Pathways relationship to erythrocyte survival |
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Definition
| provides energy for erythrocyte to maintain cell membrane properties. If the membrane cannot maintain those properties the cell becomes sodium and calcium logged (pumps), potassium depleted, water logged and changes to a sphere and removed from circulation |
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Term
| Hexose Monophosphate Shunts relationship to erythrocyte survival |
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Definition
| necessary for mainting hemoglobin in the reduced funtional state, if hemoglobin is oxidized it denatures and precipitates as heinz bodies |
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Term
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Definition
| denatured hemoglobin which attaches to the membrane (decreases flexibility) and is removed from the cell by the spleen |
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Term
| Methemoglobin reductase pathways relationship tp erythrocyte survival |
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Definition
| mantains iron in the ferrous state in hemoglobin, if this pathway does not work then methb builds up which limits the oxygen carry capacity of blood |
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Term
| Rapoport-leubering shunts relationship to survival |
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Definition
| allows for the production of 2,3-bpg which is bound by hemeglobin and allows hemoglobin to have a decreased affinity for oxygen and release it into the tissues |
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Term
| Hemoglobin is labeled for destruction when... |
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Definition
| phosphitidylserine (inner leaflet)is exposed on the outer leaflet of the membrane |
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Term
| extra cellular destruction |
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Definition
| most efficient pathway of old RBC removal via hemoglobin break down into iron, heme and globin. Iron and globin are recycled, heme is catabolized by macrophages |
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Term
| intravascular destruction |
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Definition
| hemoglobin is dissociated into dimers and bound to haptoglobin. this complex is carried to the liver and excreted |
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Term
| Intravascular destruction hemolysis levels |
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Definition
| present in: hemoglobinemia, hemoglobinuria, and hemosidrinuria, |
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Term
| extravascular destruction hemolysis levels |
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Definition
| present in: indirect bilirubin and urobilinogen |
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Term
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Definition
| stimulates erythropoiesis |
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Term
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Definition
| stimulate erythrocyte destruction |
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Term
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Definition
| predominant skeletal protein exists as a heterodimer of two large chains, functions as a spring, coiled tetramers can extend reversibly when the membrane is stretched but cannot exceed their maximum extend length without rupturing |
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Term
| Polychromatophilic erythrocyte |
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Definition
| another name for the reticulocyte because of the bluish tinge with stains due to the residual RNA and mitochondria |
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Term
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Definition
| Found primarily on the cytoplasmic face of the erythrocyte membrane and include enzymes and structural proteins |
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Term
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Definition
| erythroblasts with normal maturation |
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Term
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Definition
| transport proteins and the glycophorins (GPA, GPB and GPC), which are made up of three domains: the cytoplasmic, the hydrophobic and the extracellular |
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Term
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Definition
| when tubular cells loaded with iron are sloughed off and excreted into the urine |
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Term
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Definition
| complexed iron storage proteins |
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Term
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Definition
| glycoprotein, synthesized in the liver and combines with heme |
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Term
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Definition
| plasma glycoprotein, present in plasma, carries hemoglobin dimers to liver |
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Term
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Definition
| nucleated erythrocyte precursors in the bone marrow |
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Term
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Definition
| biliveridin reduced, released from the macrophage, bound to the plasma albumin and carried to the liver |
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Term
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Definition
| an increase in erythrocyte membrane lipids due to a disproportionate increase in cholesterol results in acanthocytes, reduced survival as compared to normal RBCs |
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