in microscopic world, countless vibrant erythrocytes, red blood cells, traverse circulatory system, tirelessly carrying

oxygencarrying erythrocytes ironrich macrocytes rbcs normocytic health hemoglobin blood erythropoiesis heme anemia erythrocyte bloodrelated hematology iron oxygenation hematologist red cell medical bloodstream hematopoiesis lifespan capillaries microcytes hematocrit morphology hypochromic ai generated