Randy Ogburn, age 11, of Winston Salem, N.C., for his question:
WHERE ARE RED BLOOD CELLS MANUFACTURED?
Your body's life stream is your blood. Food and oxygen are taken to your body cells by your blood, and waste products are carried by the blood to the organs which remove them from your body or break them down into harmless substances. Blood also helps to fight germs that may enter your body.
Of all the components in your blood, the red blood cells are the most numerous. Also called erythrocytes, their main duty is to carry oxygen from your lungs to your body tissues, and to carry carbon dioxide from the body tissues back to the lungs.
A microliter is a tiny unit of measure equal to one millionth of a liter. And in one microliter of blood you'll find between 4 and 6 million red blood cells which are constantly circulating throughout your bloodstream.
Production of red blood cells takes place in the bone marrow of your body. Needed for the process is a well balanced diet since the production requires copper, iron, proteins and several vitamins.
New blood cells, before they are ready to go to work, are larger than mature cells since they each have a nucleus. As the cells develop in the bone marrow, they acquire hemoglobin. It is the normal pattern for each cell to lose its nucleus just before it enters the blood.
The full period of red blood cell production takes about a week under normal conditions. If the oxygen content of the blood should drop, however, the kidneys will immediately release a hormone called erythropietin. This hormone forces the blood marrow to speed up its production of red blood cells. This condition happens if there is a sudden loss of blood.
A red blood cell lives in your body for about 120 days after it enters from the marrow. Old erythrocytes are taken out of the blood at a rate of about 2 million per second. They are then destroyed, chiefly by the spleen and the liver. The iron and protein of the old cells are returned to the marrow for reuse as new erythrocytes are produced.
Anemia occurs when the number of erythrocytes falls below normal. This is usually caused by a below normal production of red blood cells, the loss of blood or overactive destruction of the erythrocytes.
A mature erythrocyte has the shape of a doughnut without a hole. It is a flat disk with thick, rounded edges and a thin, indented center.
While the red blood cell does not have a nucleus, it does have a cell membrane, hemoglobin and a group of chemicals which provide energy and keep the eythrocytes in good condition.