Our individual blood group is determined by our parents at the time of our conception. Blood groups are determined by the presence of antigens (a substance capable of stimulating an immune response) on the surfaces of the red cells. Although the red blood cells in different people look the same they are, in fact, dissimilar. They can be divided up into four main groups: A, B, AB and O.
Blood can be transplanted from one person to another by what we call a blood transfusion. It is very important that the blood given matches the person’s group, because if the wrong types of blood are mixed together the result can be serious blood clots.
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Fact File: Blood begins to clot as soon as it is exposed to the air, plugging the wound. White blood cells gather around the wound to kill invading microbes, and new skin cells grow into the healing wound beneath the scab. |
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