Week 2(2) Flashcards
(42 cards)
What is the main function of red blood cells (RBCs)?
Carry oxygen from the lungs to tissues and transport carbon dioxide from tissues to the lungs.
What is erythropoiesis?
The process of RBC production.
EPO binds to receptors on early erythroid cells, reducing apoptosis and stimulating proliferation and maturation.
What are the stages of erythropoiesis?
Pronormoblast → Basophilic erythroblast → Polychromatic erythroblast → Orthochromatic erythroblast → Reticulocyte → Mature RBC
What hormone regulates erythropoiesis?
Erythropoietin (EPO), primarily produced in the kidneys in response to tissue hypoxia.
Why do mature RBCs lack a nucleus and mitochondria?
To maximize space for hemoglobin and oxygen transport.
Lack of mitochondria means RBCs rely on anaerobic glycolysis for energy.
What are the main metabolic pathways in RBCs?
Glycolysis (Embden-Meyerhof pathway) for ATP production.
Hexose Monophosphate Shunt for NADPH production.
Rapoport-Luebering Shunt for 2,3-DPG production.
What is the function of 2,3-DPG?
Regulates hemoglobin’s oxygen affinity by stabilizing its low-oxygen state.
What factors regulate EPO production?
Tissue hypoxia detected by the kidneys.
Hypoxia-Inducible Factor (HIF) activates EPO gene expression.
What proteins are essential for RBC membrane structure?
Spectrin, Ankyrin, Band 3, Glycophorin.
What are haemolytic anaemias?
RBC destruction disorders
What is hereditary spherocytosis (HS)?
A condition where RBCs assume a spherical shape due to defects in membrane proteins (e.g., spectrin, ankyrin, band 3).
What diagnostic tests confirm HS?
Osmotic fragility test.
What is hereditary elliptocytosis (HE)?
A disorder where RBCs become elliptical due to defective spectrin.
What is hereditary stomatocytosis?
A disorder where RBCs appear cup-shaped with a central slit due to membrane protein defects.
What is glucose-6-phosphate dehydrogenase (G6PD) deficiency?
reduced NADPH, making RBCs more vulnerable to oxidative stress.
What triggers haemolysis in G6PD deficiency?
Infections, certain drugs, and fava beans (favism).
How is G6PD deficiency diagnosed?
G6PD fluorescent spot test.
What is pyruvate kinase (PK) deficiency?
A metabolic disorder affecting ATP production, leading to rigid RBCs and haemolysis.
What is the osmotic fragility test used for?
Measures RBC resistance to hemolysis in hypotonic solutions; used to diagnose HS.
How do RBCs generate energy?
hrough anaerobic glycolysis (Embden-Meyerhof pathway).
What is the role of NADPH in RBCs?
Protects against oxidative stress and maintains hemoglobin in its functional state.
What is anisocytosis?
Variation in RBC shape
What is poikilocytosis?
Variation in RBC shape
What is the significance of reticulocyte count?
Measures bone marrow activity; increased in haemolysis or blood loss.
