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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. |
More than half of blood is plasma, a straw-colored liquid that is 92 percent water. The remaining eight percent of plasma contains more than 200 substances including proteins, vitamins, sugar, fats, and minerals that fight disease and act as chemical messengers.
Plasma is the circulating liquid in which red and white cells, as well as platelets, move. It carries nutrients to all parts of the body and carries off waste products.
The average adult body contains about 10-12 pints of blood, of which six pints are plasma.
Red Blood Cells give your blood its color. The red color comes from a combination of oxygen and hemoglobin, which consists of iron and other materials. The hemoglobin makes it possible for red blood cells to pick up oxygen from the air you breathe and to carry that oxygen from your lungs to the trillions of cells that make up your body.
The oxygen released by the red cells help convert nutrients in foods such as milk, red meat and green vegetables into energy.
As each red blood cell distributes its lead of oxygen to the cells, it picks up carbon dioxide and carries it back to the lungs to be exhaled.
Red Blood Cells are round and tiny, about 3,000 end-to-end would equal one inch. An average adult’s body contains about 25 trillion red blood cells, 600 – 700 times as many as white cells.
Photo Copyright: Dennis Kunkel, University of Hawaii |
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White Blood Cells are important to your body in several ways:
- They fight off infections and help you recover from viral diseases, such as chicken pox.
- They keep you from catching the same viral diseases over and over again. This is called “being immune”.
- They “eat” harmful bacteria, the kind you would have in a cut, scraped knee or in an infected ear.
An average adult’s body normally contains over 35 billion white cells – one for every 600 to 700 red cells.
Platelets are very small and irregularly shaped particles in the blood. When you get a scratch or cut that bleeds, it means that some blood vessel has been cut or broken. In the blood, near the cut, platelets become sticky, like honey. They pile together at the injury, sticking to each other to slow the flow of blood.
As more platelets gather, some break up and release chemicals, which form a web of fibrin threads. Red and white blood cells get caught in the web of fibrin, making the plug grow bigger and more solid. Finally it is a firm clot that stops the flow of blood.
The dried clot that develops as the cut begins to heal is called a scab.
Copyright 2005 Cascade Regional Blood Services
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