Linda Lamey, age 11, of Upper Durham, for her questions:
How long do red blood cells live?
A little red blood cell has a life expectancy of about 127 days and oh, what a busy life it leads. Day or night, while you are sleeping or waking, the little red saucer is swimming along in the liquid blood plasm, attending to its duties, As it circulates throughout the body, each round trip takes it back to the heart. There it is pumped on its way around again. The red cell leaving the heart is full of fresh oxygen.
On its way through the blood vessels, the red cell acts as a delivery man and a garbage man. It delivers fresh oxygen to the body cells and collects up a load of waste carbon dioxide. On it travels, now back through the veins to the lungs. There the red cell gives up its waste carbon dioxide and takes on a fresh load of oxygen. Back it goes to the heart to be pumped around the body once again. This fetching and carrying goes on day and night throughout the life of the little red cell.
The red cell is made in the marrow of the bones. It is made from proteins and iron which the body, of course, takes from the food you eat. For plenty of good red blood cells, eat green vegetables, meat and dairy products. It is important to make a habit of eating these foods, for about 200 million new red blood cells are made erery day. It takes about 60,000 of these cells to cover the head of a pin. Each one is a disk shaped sac with a thick rim and a hollow dent in the center on each side. It is covered with the thinnest of skins and filled with hemoglobin.
Thousands of brand new red cells are poured into the blood stream every minute, They take up their duties of delivering oxygen and collecting carbon dioxide and they float around in the blood stream. Meantime, an equal number of old red cells are being sent to the scrap heap. These weary workers are sent first to the spleen, a small, soft organ near the stomach.
Here the worn out red cells are broken up into various chemicals. Some of these materials are then sent out through the body as wastes. Other materials are sent along to the liver. The liver discards the red pigment color of the cells and it too leaves the body as waste material. But the iron, or some of it, which was in the old blood cells is saved. This scrap iron is sent around the body to the bone marrow where it is re used to make more new red cells.
Do not depend too much upon this thrifty saving of iron by the liver, however. Much of it is wasted and the re used iron needs a daily supply of new iron from your food. So, don't miss up on those fresh, green, iron rich vegetables for a single day.