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

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