Red Blood Cells

Red blood cells (RBCs) are found in the blood stream. Their main function is to deliver oxygen and other nutrients to every corner of the entire body and to remove carbon dioxide and other waste products from all the cells. These cells have a concave shape and contain a red pigment called hemoglobin. This red pigment gives the blood its red color. Both the shape and the hemoglobin is a perfect combination for the transport to occur. (1)


Note - erythrocyte is the medical term for a red blood cell.

RBCs release carbon dioxide and pick up oxygen in an area called the alveoli which are tiny sacs located all over the lungs. When we exhale (breathe out) the RBCs release the carbon dioxide and when we inhale (breathe in), they pick up the oxygen. This oxygen is then carried to all the cells of the body via the arteries.

When the RBCs arrive at their delivery location, another exchange occurs in the capillaries which are tiny blood vessels that connect the arteries with the veins. The RBCs drop the oxygen and the other nutrients and pick up carbon dioxide and other waste products. Once the RBCs are loaded with carbon dioxide and other waste products, they return to the lungs via the veins and the process starts all over.