Red Blood Cells
Most of the cells in the blood are red blood cells. These are highly specialized cells that have been "stripped" of everything, including the nucleus, that might get in the way of doing their major job, transporting oxygen.

Photo: Copyright Dennis Kunkel, University of Hawaii

Hemoglobin
Red blood cells are filled with a special red colored molecule called hemoglobin. It picks up oxygen in areas where oxygen is abundant and releases oxygen in tissues where the oxygen concentration is lowest.

3D Image: Copyright Bristol Productions

Additional Information

• Diseases of Red Blood Cells
• Red Blood Cell Flexibility