Erythropoiesis

• HYPOXIA: primary stimulus
• ERYTHROPOIETIN : produced in the KIDNEY
• Blasts

  • Fine chromatin
  • Presence of nucleoli
  • Large size
  • Basophilic cytoplasm
  • Absence of granules
  • Large nucleus
  • High N/C ratio
• RBC Maturation

  • RubriPro
  • ProBaso
  • RubriPoly
  • MetaOrtho
• it takes about one week for the BFU-E to mature to the CFU-E and another week for the CFU-E to become a pronormoblast, which is the first morphologically identifiable RBC precursor
• 1st stage : Pronormoblast/Rubriblast/ Proerythroblast

  ❑ Diameter = 14-20 um

  ❑ Deeply basophilic cytoplasm

  ❑ Non-granular w/ fine chromatin

  ❑ N/C ratio = 8:1

  ❑ With 1-2 nucleoli
• 2ND STAGE

  
  

  Basophilic Normoblast/ Basophilic Erythroblast/ Prorubricyte

  ❑ Diameter = 12-17 um

  ❑ Intensely basophilic cytoplasm

  ❑ Chromatin slightly coarse

  ❑ N/C ratio = 6:1

  ❑ Nucleoli not usually visible
• 3RD STAGE

  
  

  Polychromatophilic Normoblast /Polychromic Erythroblast

  ✔ LAST STAGE CAPABLE OF MITOSIS

  ✔ HEMOGLOBIN SYNTHESIS BEGINS

  ❑ Murky blue-gray to pink-gray

  cytoplasm

  ❑ Diameter = 10-15 um

  ❑ N/C ratio = 4:1
• 4TH STAGE

  
  

  Orthochromic Normoblast/ Orthochromic Erythroblast/Metarubricyte

  ❑ Diameter = 7-12 um

  ❑ Pink cytoplasm w/ small pyknotic nucleus

  ❑ N/C ratio = 1:2

  ✔ LAST NUCLEATED STAGE
• 5TH STAGE

  
  

  Reticulocyte/Polychromatophilic Erythrocyte

  ✔ INDEX OF BONE MARROW ACTIVITY

  ✔ LAST STAGE WITH HEMOGLOBIN SYNTHESIS

  ❑ Diameter = 7-10 um

  ❑ Pink to slightly pinkish gray cytoplasm

  ❑ Contains fine basophilic reticulum of RNA

  which is only visible with SUPRAVITAL

  STAIN

  ❑ Brilliant Cresyl Blue

  ❑ New Methylene Blue
• 6TH STAGE

  
  

  Mature Erythrocyte

  ❑ Red Blood Cells/ Discocyte

  ❑ Diameter = 6-8 um

  ❑ Non-nucleated, round and biconcave with a

  central pallor 1/3 of its size

  ❑ Pink in color (Salmon-pink)

  ✔ NOT CAPABLE OF HGB SYNTHESIS

  ✔ Highest in the MORNING

  ✔ Life span: 120 days
• LAST STAGE CAPABLE OF MITOSIS: Polychromatophilic normoblast
• Last Nucleated stage: Orthochromatophilic normoblast
• INDEX OF BM ACTIVITY: Retics
• HGB Synthesis:

  START: Pronormoblast

  END: Polychromatophilic Erythrocyte (Reticulocyte)
• EMBRYONIC HEMOGLOBINS

  ❑ Portland = 2 zeta + 2 gamma

  ❑ Gower 1 = 2 zeta+ 2 epsilon (FIRST TO APPEAR)

  ❑ Gower 2 = 2 alpha + 2 epsilon
• FETAL HEMOGLOBINS

  ❑ HbF = 2 alpha + 2 gamma

  ❑ HbA = 2 alpha +2 beta

  ❑ HbA2 = 2 alpha + 2 delta
• HLA on RBC: BENNETT-GOODSPEED

  □ Bga : HLA-B7

  □ Bgb : HLA-B17

  □ Bgc : HLA-A28
• Visible with SUPRAVITAL STAIN (RHH)

  ❑ Reticulum of reticulocytes

  ❑ Heinz bodies

  ❑ HbH
• Stages of RBC Precursors

  
  

  1. Rubriblast
  2. Prorubricyte
  3. Rubricyte
  4. Metarubricyte
  5. Reticulocyte
  6. Mature Erythrocyte / Discocytes
• RBC Maturation Series

  1. Basophillic Normoblast
  2. Polychromatophilic normoblast
  3. orthochromic normoblast
  4. Polychromatophilic erythrocyte
  5. Mature Erythrocytes
• RBC Maturation Series

  1. Basophilic erythroblast
  2. Polychromatic erythroblast
  3. Orthochromic erythroblast
  4. Diffusely basophilic erythrocyte
• Polychromatophilic Normoblast /Polychromic Erythroblast

  ✔ LAST STAGE CAPABLE OF MITOSIS

  ✔ HEMOGLOBIN SYNTHESIS BEGINS
• Reticulocyte/Polychromatophilic Erythrocyte

  ✔ INDEX OF BONE MARROW ACTIVITY

  ✔ LAST STAGE WITH HEMOGLOBIN SYNTHESIS
• Orthochromic Normoblast/ Orthochromic Erythroblast/Metarubricyte

  ✔ LAST NUCLEATED STAGE
• Polychromatophilic Normoblast /Polychromic Erythroblast

  ✔ LAST STAGE CAPABLE OF MITOSIS

  ✔ HEMOGLOBIN SYNTHESIS BEGINS
• Reticulocyte/Polychromatophilic Erythrocyte : Diameter = 7-10 um
• Mature Erythrocyte: NOT CAPABLE OF HGB SYNTHESIS
• Mature Erythrocyte: Highest in the MORNING
• Up to 16 orthochromic normoblasts are produced from a single pronormoblast.
• Orthochromic Erythroblast/ Metarubricyte: Pink cytoplasm w/ mall pyknotic nucleus
• Polychromic Erythroblas: N/C ratio = 4:1
• Basophilic Erythroblast/ Prorubricyte: Nucleoli not usually visible
• Rubriblast/ Proerythroblast: Deeply basophilic cytoplasm
• Reticulocytes: Found in peripheral blood