RED BLOOD CELL II

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RED BLOOD CELL II (METABOLISM FUNCTION)
SAWITREE CHIAMPANICHAYAKUL DEPARTMENT OF CLINICAL
MICROSCOPY FACULTY OF ASSOCIATED MEDICAL SCIENCES
CHIANG MAI UNIVERSITY
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RED CELL PRODUCTION
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Mature red cell

• no nucleus
• no mitochondria
• no ribosome

FA oxidation, TCA cycle
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Red Cell Metabolism
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Metabolism in Erythrocyte
1. Embden-Meyerhof (Glycolysis) Pathway 2.
Methemoglobin Reductase Pathway 3. Luebering
Rapaport Pathway 4. Hexose Monophosphate (Pentose
Phosphate) Pathway
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Embden-Meyerhof Pathway

• 90 glucose
• anaerobic glycolysis
• breakdown glucose to lactate
• generate 2 ATPs
• Glucose 2ADP 2Pi 2 lactate 2ATP H2O
• maiatains pyridine nucleotides (reduced state)

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Hexokinase
Phosphofructokinase
Phosphoglyceratekinase
Pyruvate kinase
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• shape (biconcave)
• flexibility
• membrane lipids
• maintain ions (Na, K,Ca2)

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Metabolism in Erythrocyte
1. Embden-Meyerhof (Glycolysis) Pathway 2.
Methemoglobin Reductase Pathway 3. Luebering
Rapaport Pathway 4. Hexose Monophosphate (Pentose
Phosphate) Pathway
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Methemoglobin Reductase Pathway

• NADH
• depend on Embden-Meyerhof pathway
• prevent the oxidation of heme iron
• Hb (Fe2) MetHb (Fe3)
• MetHb (transport function is lost)

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Hexokinase
Pyruvate kinase
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Glucose
Glyceraldehyde-3P
Methemoglobin Reductase Pathway
Hb (Fe2)
NAD
MetHb (Fe3)
NADH
1,3 DPG
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Methemoglobin Reductase Pathway
Glucose
Glyceraldehyde-3P
Hb (Fe2)
NAD
MetHb
NADH
MetHb (Fe3)
1,3 DPG
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Metabolism in Erythrocyte
1. Embden-Meyerhof (Glycolysis) Pathway 2.
Methemoglobin Reductase Pathway 3. Luebering
Rapaport Pathway 4. Hexose Monophosphate (Pentose
Phosphate) Pathway
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Luebering Rapaport pathway

• produce 2,3-diphosphoglycerate (2,3-DPG)
• important in oxygen-carrying capability

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Hexokinase
Pyruvate kinase
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Hexokinase
2,3-DPG
Pyruvate kinase
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Hexokinase
2,3-DPG
Pyruvate kinase
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Metabolism in Erythrocyte
1. Embden-Meyerhof (Glycolysis) Pathway 2.
Methemoglobin Reductase Pathway 3. Luebering
Rapaport Pathway 4. Hexose Monophosphate (Pentose
Phosphate) Pathway
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Hexose Monophosphate (Pentose Phosphate) Pathway

• 10 glucose
• oxidation catabolism of glucose reduction of
• NADP to NADPH
• no ATP
• produce NADPH

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G6PD deficiency

• Methemoglobin
• lipid peroxidation

Glucose-6-phosphate dehydrogenase
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HMP pathway
Insufficient of reduced glutathione (GSH)
oxidants
Heinz body
Phagocytosis
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Metabolic Pathways in the Erythrocyte
Metabolic Pathway Function Embden-Meyerhof
pathway Maintains cellular energy by
generating ATP Hexose monophosphate shunt
Prevents denaturation of globin of the
Hb molecule by oxidation Methemoglobin
reductase pathway Prevents oxidation of
heme iron Luebering-Rapaport pathway
Regulates oxygen affinity of Hb
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Catabolism of Erythrocyte

• Extravascular catabolism
• 90 destruction
• Intravascular catabolism
• 10 destruction

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An Erythrocyte ages
1. Membrane becomes less flexible 2.
Concentration of intracellular Hb increase 3.
Enzyme activity(glycolysis) diminishes
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Extravascular catabolism
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Intravascular catabolism
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Red Cell Function
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Red Cell Function

• Transport gas
• O2 to tissue
• CO2 to lung
• Acid-base equilibium

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Hemoglobin
Heme
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Hemoglobin oxygen dissociation curve
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CO2
O2
tissue
Plasma
RBC
HHb O2
Carbonic anhydrase
CO2 H2O HCO3- H
HbO2
Bd3
HCO3-
Cl-
lung
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Cl-
tissue
HCO3-
Plasma
Bd3
Cl-
HbO2
Carbonic anhydrase
H HCO3- CO2 H2O
HHb O2
lung
CO2
O2
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References
1. Hoffbrand AV, Pettit JE, Moss PAH. Essential
Haematology, 4th Ed. Blackwell Scientific
Publication,Oxford, 2001. 2. Turgeon ML. Clinical
Hematogy (Theory and Procedures), 3nd Ed,
Lippincott Williams Wilkins, Philadephia,
1999. 3. Mehta AB and Hoffbrand AV. Haematology
at a Glance, 1st Ed. Blackwell Scientific
Publication,Oxford, 2000. 4. Hillman RS and
Finch CA. Red Cell Manual, 5th Ed, F.A. Davis
company, Philadephia, 1985.