RBC Production and Survival Flashcards
Outline the steps of Erythropoiesis
What regulates erythropoiesis?
- Stem cell → proerythroblast → erythroblast → erythrocyte
- Regulated by blood O2. ↓pO2 = ↑erythropoietin release from kidneys = ↑erythropoiesis
What is the role of Iron, Vit B12, and Folate in RBC production and survival?
What causes the deficiency of Iron, Vit B12, and Folate, and what are their clinical effects?
- Iron is needed for the synthesis of Hb. Vitamin B12 and Folate act as a coenzyme in RBC maturation and DNA synthesis.
- Iron deficiency is caused by ↓red meat/vegetable intake, ↓absorption, ↓chronic blood loss, ↑demand during pregnancy.
Vitamin B12 deficiency is caused by inadequate intake and disorders in B12 absorption - Intrinsic factor used in its reabsorption.
Folate deficiency is caused by inadequate intake, absorption defect, ↑demand, antifolaxe drugs.
What are the roles of G6PD and PK (Pyruvate Kinase) in RBC survival?
What occurs when they’re deficient?
- Both enzymes support the Pentose Phosphate and Glycolytic Pathways.
- In G6PD deficiency, ↓NADPH/GSH production. In PK deficiency, there’s ↓ATP, which prevents the cation pumps form working, leading to ↑K+/water loss = chronic haemolytic anaemia. Excess haemolysis (RBC breakdown) = Jaundice (due to excess bilirubin) and Gallstones.
Outline Hereditary/Acquired Haemolytic Anaemia
Acquired - can be immune (drug-induced) or non-immune (secondary infection)
Hereditary - can be RBC membrane disorder, sickle cell, or thalassaemia
