Blood is typed orclassified according to the different genetically inherited proteins on the surface of red blood cells and antibodies in the plasma. These antigens affect the ability of the red blood cells to provoke an (1) ________. More than 20 groups of these proteins have now been identified, but the most familiar are the AB0 and Rh blood groups.
There are two main (2) ________: the AB0 system and the rhesus system.
In the AB0 system, the presence or absence of 2 types of antigen (named A and B) on the surface of the red blood cells determine whether a person’s blood group is A, B, AB (which has both A and B), or 0 (which has neither A nor B). People with the A antigen (group A) have anti-B antibodies; people with the B antigen (group B) have anti-A antibodies; those with both antigens (blood group AB) have neither; and those with neither antigen (group 0) have both. A and B are considered to be (3) ________, which means a child inheriting an A blood type from the mother and a B blood type from the father will most likely have an AB blood type. Only two (4) ________ 0 blood type genes from both parents will result in a child having an O blood type. People with type 0 blood are called (5) ________, because their blood can be given to people with any of the AB0 types.
Rh blood group systemclassifies blood groups according to the presence or absence of the Rh antigen, often called the (6) ________, on the cell membranes of the red blood cells. People with this factor are (7) ________; those without it are (8) ________. The importance of the Rh group relates mainly to pregnancy in Rh-negative women, since, if the baby is Rh positive, the mother may form antibodies against the baby’s blood.
In giving blood transfusions, it is important to use blood that is the same type as the recipient’s blood or a type to which the recipient will not show an immune reaction. Mismatches with the AB0 and Rh blood types are responsible for the most serious, sometimes life-threatening, (9) ________.