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

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