Hematology and Oncology Book

Anemia

  • Red Blood Cell Physiology

Cardiovascular Medicine

http://www.fpnotebook.com/

Red Blood Cell PhysiologyAka: Hemoglobin Production, Iron

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  1. Physiology: Erythropoietin
    1. Primary hormone regulator of RBC production
    2. Erythropoietin sources
      1. Fetus: Monocyte and Macrophage system in liver
      2. Postnatal: Peritubular cells in kidney
  2. Physiology: Iron
    1. Total Body Iron
      1. Men: 50 mg/kg (or 3.8 grams for 75 kg man)
      2. Women: 42 mg/kg (or 2.3 grams for 55 kg woman)
    2. Normal adult iron distribution
      1. Functional iron (70%)
        1. Hemoglobin component (80%)
        2. Myoglobin
        3. Intracellular respiratory enzymes (cytochromes)
      2. Storage or transport iron (30%)
        1. Ferritin (primary storage)
        2. Hemosiderin
        3. Transferrin (iron transport)
    3. Iron Loss
      1. Men and non-menstruating women: 1 mg iron/day
      2. Menstruating women: 1.6 to 2.5% more per day
        1. Blood loss varies widely per Menstrual Cycle
        2. Average loss: 10 mg iron/cycle
        3. Blood loss may approach 42 mg/cycle in heavy flow
      3. Pregnancy: 700 mg iron lost
      4. Whole blood donation (500 cc): 250 mg iron lost
  3. Physiology: Red Blood Cell
    1. Hemoglobin produced until amounts to 90% of RBC mass
    2. Red Blood Cells start as Reticulocytes in Bone Marrow
      1. Reticulocytes are juvenile Red Blood Cells
        1. Nucleus extruded once RBC has matured
        2. Reticulocytes contain ribosome remnants
          1. Immature Reticulocytes contain most ribosomes
          2. Mature Reticulocytes contain least ribosomes
      2. Reticulocytes have 4 day life span
        1. Bone Marrow: 3 days (less if Erythropoietin high)
        2. Peripheral blood: 1 day
    3. Red Blood Cell survival
      1. Normal RBC: 120 days
      2. Abnormal RBC: May survive as little as 15 days
      3. Following transfusion: RBC survival 2-3 weeks
  4. Physiology: Hemoglobin
    1. Heme protein complex of 2 pairs of polypeptides
    2. Six types of normal Hemoglobin
      1. Embryonic
      2. Gower I
      3. Gower II
      4. Portland
      5. Fetal Hemoglobin (HbF)
        1. Primary Hemoglobin in fetus
        2. Replaced by Adult Hemoglobin by age 6-12 months
      6. Adult Hemoglobin (HbA and HbA2)
  5. References
    1. (1998) MMWR Morb Mortal Wkly Rep 47:1
  6. Resources
    1. MMWR Iron Deficiency Anemia Prevention
      1. http://www.cdc.gov/mmwr/pdf/rr/rr4703.pdf

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