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Red Blood Cell Physiology
Aka: Red Blood Cell Physiology, Hemoglobin Production, Hemoglobin A2, Hemoglobin A, Hemoglobin F, Hemoglobin H, Hemoglobin Bart, Iron
- Physiology: Erythropoietin
- Primary hormone regulator of RBC production
- Erythropoietin sources
- Fetus: Monocyte and Macrophage system in liver
- Postnatal: Peritubular cells in Kidney
- Physiology: Iron
- Total Body Iron
- Men: 50 mg/kg (or 3.8 grams for 75 kg man)
- Women: 42 mg/kg (or 2.3 grams for 55 kg woman)
- Normal adult iron distribution
- Functional iron (70%)
- Hemoglobin component (80%)
- Myoglobin
- Intracellular respiratory enzymes (cytochromes)
- Storage or transport iron (30%)
- Ferritin (primary storage)
- Hemosiderin
- Transferrin (iron transport)
- Iron Loss
- Men and non-menstruating women: 1 mg iron/day
- Menstruating women: 1.6 to 2.5% more per day
- Blood loss varies widely per Menstrual Cycle
- Average loss: 10 mg iron/cycle
- Blood loss may approach 42 mg/cycle in heavy flow
- Pregnancy: 700 mg iron lost
- Whole blood donation (500 cc): 250 mg iron lost
- Physiology: Red Blood Cell
- Hemoglobin produced until amounts to 90% of RBC mass
- Red Blood Cells start as Reticulocytes in Bone Marrow
- Reticulocytes are juvenile Red Blood Cells
- Nucleus extruded once RBC has matured
- Reticulocytes contain ribosome remnants
- Immature Reticulocytes contain most ribosomes
- Mature Reticulocytes contain least ribosomes
- Reticulocytes have 4 day life span
- Bone Marrow: 3 days (less if Erythropoietin high)
- Peripheral blood: 1 day
- Red Blood Cell survival
- Normal RBC: 120 days
- Abnormal RBC: May survive as little as 15 days
- Following transfusion: RBC survival 2-3 weeks
- Physiology: Hemoglobin
- Heme protein complex
- Central iron-containing heme ring attached to
- Two pairs of polypeptides (4 total)
- A pair of alpha chains are found in every normal Hemoglobin type
- A pair of other polypetides depending on type (Gamma, Beta, Delta)
- Six types of normal Hemoglobin
- Embryonic
- Gower I
- Gower II
- Portland
- Fetal Hemoglobin (HbF): Alpha2-Gamma2
- Primary Hemoglobin in fetus
- Replaced by Adult Hemoglobin by age 6-12 months
- Adult Hemoglobin (HbA): Alpha2-Beta2
- Adult Hemoglobin (HbA2): Alpha2-Delta2
- Thalassemia related Hemoglobins
- Hemoglobin Bart's: Gamma4
- Seen in Alpha Thalassemia
- Hemoglobin H: Beta4
- Seen in Beta Thalassemia
- References
- (1998) MMWR Morb Mortal Wkly Rep 47:1-29
- Resources
- MMWR Iron Deficiency Anemia Prevention
- http://www.cdc.gov/mmwr/pdf/rr/rr4703.pdf