Red blood cells make up almost 45 percent of the blood volume. Their primary function is to carry oxygen from the lungs to every cell in the body. Red blood cells are composed predominantly of a protein and iron compound, called hemoglobin, that captures oxygen molecules as the blood moves through the lungs, giving blood its red color. As blood passes through body tissues, hemoglobin then releases the oxygen to cells throughout the body. Red blood cells are so packed with hemoglobin that they lack many components, including a nucleus, found in other cells.
The membrane, or outer layer, of the red blood cell is flexible, like a soap
bubble, and is able to bend in many directions without breaking. This is
important because the red blood cells must be able to pass through the
tiniest blood vessels, the capillaries, to deliver oxygen wherever it is
needed. The capillaries are so narrow that the red blood cells, normally
shaped like a disk with a concave top and bottom, must bend and twist to
maneuver single file through them.
| Conceived by Ajit Kumar , contact me at mr_ajit_kumar@indiatimes.com |