erythropoiesis_hematology

• What is the process of development, differentiation, and maturation of RBCs from primitive stem cells called?

  Erythropoiesis
• What are the nomenclature terms for erythroid precursors?

  • Erythroblast
  • Normoblast
  • Rubri
  • Proerythroblast
  • Pronormoblast
  • Rubriblast
  • Basophilic Erythroblast
  • Basophilic Normoblast
  • Prorubricyte
  • Polychromatophilic Erythroblast
  • Polychromatophilic Normoblast
  • Rubricyte
  • Orthochromic Erythroblast
  • Orthochromic Normoblast
  • Metarubricyte
  • Polychromatophilic Erythrocyte
  • Reticulocyte
  • Mature Erythrocyte
• What is Erythropoietin (EPO)?


  A thermostable, nondialyzable, glycoprotein hormone with a molecular weight of 34 kiloDalton
• Where is Erythropoietin produced and where does it act?

  Produced in the kidney and acts in the bone marrow
• What are the functions of Erythropoietin (EPO)?

  • Accelerates the rate of mRNA and protein (hemoglobin) synthesis
  • Decreases the time for the maturation of metarubricyte
  • Stimulates the premature release of immature RBCs (Reticulocytes) from the bone marrow
  • Increases the rate of extrusion of a red blood cell nucleus (enucleation)
• What are the three major effects of Erythropoietin (EPO)?


  • Allowing early release of reticulocytes from the bone marrow
  • Preventing apoptotic cell death
  • Reducing the transit time for cells to mature in the bone marrow
• What happens to a pronormoblast during erythropoiesis?

  It undergoes mitosis and gives rise to two daughter pronormoblasts
• What is the diameter of a pronormoblast?

  12 to 19 µm
• What is the N:C ratio of a pronormoblast?

  About 8:1
• What characteristics define a basophilic normoblast?

  Intensely basophilic cytoplasm, N/C ratio of about 6:1, and slightly coarse chromatin
• What is the diameter of a basophilic normoblast?

  12-17 µm
• What is the appearance of the chromatin in a basophilic normoblast?

  Chromatin may be partially clumped and suggest a wheel with broad spokes
• What is the significance of the polychromatophilic normoblast stage?


  It is the last stage capable of mitosis and the first stage of hemoglobin synthesis
• What is the diameter of a polychromatophilic normoblast?

  11-15 µm
• What is the N:C ratio of a polychromatophilic normoblast?

  About 4:1
• What is the appearance of the cytoplasm in a polychromatophilic normoblast?

  Blue-gray to pink-gray or muddy/murky light gray cytoplasm
• What characterizes the orthchromic normoblast stage?

  The nucleus is completely dense (pyknotic) and it is incapable of mitosis
• What is the diameter of an orthchromic normoblast?

  1. 12 µm
• What is the N:C ratio of an orthchromic normoblast?

  About 1:2
• What is the appearance of the cytoplasm in a polychromatophilic erythrocyte?

  Pink to slightly pinkish gray cytoplasm
• What is the diameter of a polychromatophilic erythrocyte?

  1. 10 µm
• What happens to a reticulocyte within 24 to 48 hours?

  It loses organelles and assumes a biconcave shape
• What is the average lifespan of an erythrocyte?

  120 ± 20 days
• What is the structure of a mature erythrocyte?

  Non-nucleated, round, biconcave disc with a central pallor
• What is the diameter of a mature erythrocyte?

  1. 8 µm
• What is the color of a mature erythrocyte?

  Salmon-pink
• What organelles are absent in mature erythrocytes?

  Mitochondria