Red Blood Cell Metabolism Flashcards
Discuss how RBCs keep a reduced atmosphere? (Pathway)
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What happens if G6PD is deficient?
NADPH levels are decreased and gluthathione is oxidized; Lack of reduced gluthathione results in an accumulation of H202, which oxidizes thiol groups on proteins. These denatured proteins aggregate and form Heinz bodies.
What happens once Heinz bodies are formed?
The granules distort RBC morphology and they will be lysed in the spleen; Hemolytic Anemia
Predict hemolytic anemia results
Low: HCT, Hgb, RBC
High: Direct/Indirect Bilirubin, Reticulocytes
What is the danger of a G6PD deficiency when an infection is present?
NADPH is required for initiating an oxidative burst.
What is the danger of anti-malarial drugs when a G6PD deficiency is present?
Anti-malarial drugs accept electrons from NADPH, decreaising the amount available even further; Leading to hemolytic anemia.
What do reticulocytes have that erythrocytes dont?
Mitochondria; Can produce ATP by glycolysis and Oxidative Phosphorylation.
Discuss the consequences of a pyruvate kinase deficiency.
Results in an accumulation of products prior to the block (PEP, G3P, and G2P) as well as a decrease in products after the block (Pyr, Lac, ATP); An absence in ATP will change the plasma membrane shape, cell will lyse.
Describe the effects of erythroid specific molecules are defective.
An imbalance in alpha and beta chains in hemoglobin could occur; Thalassemias can occur. The other option is the formation of abnormal alpha or beta chains; Sickle cell.
Discuss alpha thalassemia
Defect in the alpha chain production and the result of excess beta chains as compared to alpha chains; Beta chains will aggregate and retain ability to bind oxygen but they’re unstable and RBC will confer abnormal morphology.
Discuss beta thalassemia
Defect in Beta chain production and the result is the presence of more alpha chains than beta chains; Can result in hemosiderosis.
Discuss Sickle Cell Anemia
Autosomal recessive condition caused by a transversion mutation; Causes a hydrophobic pocket in both oxygenated and deoxygenated states. The pocket binds to a groove only in dexoygenated state. Hb molecules will bind only if pocket and groove are present.
