Blood carries gases, nutrients and waste products through the body. Blood also fights infections, heals wounds and performs many other vital functions. There is no substitute for blood. It cannot be made or manufactured. Donors are the only source of blood for patients who need it.
One unit of blood can be separated into components: red blood cells, white blood cells, plasma, platelets and cryoprecipitate.
What is Blood?
| Red cells, white cells and platelets are made in the marrow of bones, especially the vertebrae, ribs, hips, skull and sternum. These essential blood cells fight infection, carry oxygen and help control bleeding. |  |
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| Plasma is a pale yellow mixture of water, proteins and salts. One of the functions of plasma is to act as a carrier for blood cells, nutrients, enzymes and hormones. |
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Red blood cells are disc-shaped cells containing hemoglobin, which enables
the cells to pick up and deliver oxygen to all parts of the body, then
pick up carbon dioxide and remove it from tissues.
Photo Copyright: Dennis Kunkel,
University of Hawaii |
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White cells are the body's primary defense against infection. They can
move out of the blood stream and reach tissues being invaded by microbes
and foreign bodies.
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The approximate distribution of blood types in the U.S. population (distribution
is different for specific racial and ethnic groups): |
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| O+ | 38%* |
| O- | 7%* |
| A+ | 34% |
| A- | 6% |
| B+ | 9% |
| B- | 2% |
| AB+ | 3%** |
| AB- | 1%** |
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Information provided by the American Association
of Blood Banks.
