Normal red blood cell and a sickle cell. Sickle cell anemia is an inherited blood disease. In normal red blood cells hemoglobin carries oxygen from the lungs to organs and tissues and brings back carbon dioxide to the lungs. In sickle cell anemia hemoglobin is defective. After carrying oxygen to organs and tissues some cells may cluster together and form rod-like structures causing the red blood cell to become stiff and to form the sickle shape. SEM X7000 at 4" x 6"