Randy Brasher, Age 9., Of Manchester' Tenn., for his question:
What is meant by different blood types?
When you go to a hospital you are given a number of tests. Chances are the experts will take a sample of your blood. They will find out and perhaps tell you the blood type to which you belong. You may belong in book group 0 or a, in b or in ab. At one time a doctor had to know your blood type if he planned to perform an operation.
The bright red color of blood comes from billions of swarming cells called corpuscles. There are so many of these little round midgets that you might think blood is made entirely of red corpuscles. But this is not so. There are also assorted white blood cells. And red cells and white cells all float freely in a stream of strawcolored liquid called blood plasma.
At one time operations were very risky because so many patients died from loss of blood. Then it was discovered that a healthy person could give or donate some of his blood to the victim of an accident or to someone recovering from surgery. This exchange was called a blood transfusion and it did not always work. Sometimes the blood from the healthy person caused the red cells of the patient to clump together and the patient died. But sometimes the transfusions worked.
About 30 years ago doctors learned why some persons can exchange their blood and some cannot. All human blood is a stream of liquid plasma teeming with red cells and white cells. But blood comes in different types. Some types carry chemicals that upset the red cells carried by other types of blood. If a person gets a transfusion from the wrong blood type, the chemicals in the donor’s blood caused the red cells of the patient to clog together in clumps.
There are four main blood types, and most experts call them groups 0 and a., b and ab. Most people in the world belong to blood group 0. This popular type of blood is the safest for transfusions. It does not harp the red cells of .other persons with 0 type blood or those with types a or b or ab type blood but an 0 ;type per on may be given only blood from another 0 type the a type blood clumps with b type„ but a person with ab type blood may get a safe transfusion from the same blood type or from any of the other three blood types, nowadays a patient may have a safe transfusion even when there is no to check his blood type. Instead of whole blood he will be given blood plasma., this is the liquid stream in which the red and white corpuscles float, these cells make up a little more than half of the blood and they are taken out when the whole blood is put into a Whirling machine. The plasma that remains is less than half the amount of the whole blood but it will give a safe transfusion to persons of every blood type.